| Message ID | 20220823102913.4181217-1-Shyam-sundar.S-k@amd.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | platform/x86/amd/pmf: Introduce CnQF feature for AMD PMF | expand |
Hi, On 8/23/22 12:29, Shyam Sundar S K wrote: > In this series, support for following features has been added. > - "Cool n Quiet Framework (CnQF)" is an extension to the static slider, > where the system power can be boosted or throttled independent > of the selected slider position. > - On the fly, the CnQF can be turned on/off via a sysfs knob. Thank you. I think that before doing a more in detail review we first need to agree on the userspace interactions here. I've added Bastien, the power-profiles-daemon maintainer to the Cc for this. From a quick peek at the patches I see that currently they do the following: Probe time: ----------- 1. If static slider (classic /sys/firmware/acpi/platform_profile) is available register as a platform_profile provider 2. Query if the BIOS tells us that CnQF should be enable by default if yes then unregister the platform_profile provider and enable CnQF Run time: --------- Allow turning CnQF on/off by writing a sysfs attribute for this. 1. When CnQF gets enabled unregister the platform_profile provider 2. When CnQF gets disabled restore the last set profile and register the platform_profile provider Questions/remarks: 1. If you look at 1. and 2. under "Probe time", you will see that when the BIOS requests to have CnQF enabled by default that userspace will then still shortly see a platform_profile provider. This must be fixed IMHO by checking whether to do CnQF by default or not before the initial register call. 2. What about low-power scenarios ? Currently power-profiles-daemon will always advertise a low-power mode even when there is no platform-profile support, since this is also a hint for other parts of the system to try and conserve power. But when this mode is enabled we really want the system to also behave as if the old static slider mode is active and set to low-power. Some ideas: a) maybe still have the amd-pmf code register a (different) platform_profile provider whn in CnQF mode and have it only advertise low-power b) teach power-profiles-daemon about CnQF and have it disable CnQF when entering low-power mode? c) make the CnQF code in PMF take the charge level into account and have it not go "full throttle" when the chare is below say 25% ? 3. Bastien, can power-profiles-daemon deal with /sys/firmware/acpi/platform_profile disappearing or appearing while it is running? Regards, Hans > > Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com> > > Shyam Sundar S K (4): > platform/x86/amd/pmf: Add support for CnQF > platform/x86/amd/pmf: Add sysfs to toggle CnQF > Documentation/ABI/testing/sysfs-amd-pmf: Add ABI doc for AMD PMF > MAINTAINERS: Update ABI doc path for AMD PMF > > Documentation/ABI/testing/sysfs-amd-pmf | 11 + > MAINTAINERS | 1 + > drivers/platform/x86/amd/pmf/Makefile | 2 +- > drivers/platform/x86/amd/pmf/acpi.c | 10 + > drivers/platform/x86/amd/pmf/cnqf.c | 374 ++++++++++++++++++++++++ > drivers/platform/x86/amd/pmf/core.c | 16 +- > drivers/platform/x86/amd/pmf/pmf.h | 100 +++++++ > 7 files changed, 512 insertions(+), 2 deletions(-) > create mode 100644 Documentation/ABI/testing/sysfs-amd-pmf > create mode 100644 drivers/platform/x86/amd/pmf/cnqf.c >
On Thu, 1 Sept 2022 at 13:16, Hans de Goede <hdegoede@redhat.com> wrote: > > Hi, > > On 8/23/22 12:29, Shyam Sundar S K wrote: > > In this series, support for following features has been added. > > - "Cool n Quiet Framework (CnQF)" is an extension to the static slider, > > where the system power can be boosted or throttled independent > > of the selected slider position. > > - On the fly, the CnQF can be turned on/off via a sysfs knob. > > Thank you. I think that before doing a more in detail review > we first need to agree on the userspace interactions here. > > I've added Bastien, the power-profiles-daemon maintainer > to the Cc for this. > > From a quick peek at the patches I see that currently they do > the following: > > Probe time: > ----------- > > 1. If static slider (classic /sys/firmware/acpi/platform_profile) > is available register as a platform_profile provider > > 2. Query if the BIOS tells us that CnQF should be enable by > default if yes then unregister the platform_profile provider > and enable CnQF > > > Run time: > --------- > > Allow turning CnQF on/off by writing a sysfs attribute for this. > > 1. When CnQF gets enabled unregister the platform_profile provider > > 2. When CnQF gets disabled restore the last set profile and > register the platform_profile provider > > > Questions/remarks: > > 1. If you look at 1. and 2. under "Probe time", you will see that > when the BIOS requests to have CnQF enabled by default that > userspace will then still shortly see a platform_profile > provider. This must be fixed IMHO by checking whether to do > CnQF by default or not before the initial register call. > > 2. What about low-power scenarios ? Currently power-profiles-daemon > will always advertise a low-power mode even when there is no > platform-profile support, since this is also a hint for other > parts of the system to try and conserve power. But when this > mode is enabled we really want the system to also behave as > if the old static slider mode is active and set to low-power. > > Some ideas: > a) maybe still have the amd-pmf code register a (different) > platform_profile provider whn in CnQF mode and have it only > advertise low-power > > b) teach power-profiles-daemon about CnQF and have it > disable CnQF when entering low-power mode? > > c) make the CnQF code in PMF take the charge level into > account and have it not go "full throttle" when the chare > is below say 25% ? > > 3. Bastien, can power-profiles-daemon deal with > /sys/firmware/acpi/platform_profile disappearing or > appearing while it is running? No, it doesn't. It expects the platform_profile file to be available on startup, at worse with the choices not yet filled in. It doesn't handle the platform_profile file going away, it doesn't handle the platform_profile_choices file changing after it's been initially filled in, and it doesn't support less than one power profile being made available, and only supports hiding the performance profile if the platform doesn't support it. Some of those things we could change/fix, some other things will not. If the platform_profile_choices file only contained a single item, then power-profiles-daemon would just export the "low-power" and "balanced" profiles to user-space, as it does on unsupported hardware. The profiles in power-profiles-daemon are supposed to show the user intent, which having a single setting would effectively nullify. It's unclear to me how CnQF takes user intent into account (it's also unclear to me how that's a low-power setting rather than a combination of the existing cool and quiet settings).
Hi, On 9/1/22 14:24, Bastien Nocera wrote: > On Thu, 1 Sept 2022 at 13:16, Hans de Goede <hdegoede@redhat.com> wrote: >> >> Hi, >> >> On 8/23/22 12:29, Shyam Sundar S K wrote: >>> In this series, support for following features has been added. >>> - "Cool n Quiet Framework (CnQF)" is an extension to the static slider, >>> where the system power can be boosted or throttled independent >>> of the selected slider position. >>> - On the fly, the CnQF can be turned on/off via a sysfs knob. >> >> Thank you. I think that before doing a more in detail review >> we first need to agree on the userspace interactions here. >> >> I've added Bastien, the power-profiles-daemon maintainer >> to the Cc for this. >> >> From a quick peek at the patches I see that currently they do >> the following: >> >> Probe time: >> ----------- >> >> 1. If static slider (classic /sys/firmware/acpi/platform_profile) >> is available register as a platform_profile provider >> >> 2. Query if the BIOS tells us that CnQF should be enable by >> default if yes then unregister the platform_profile provider >> and enable CnQF >> >> >> Run time: >> --------- >> >> Allow turning CnQF on/off by writing a sysfs attribute for this. >> >> 1. When CnQF gets enabled unregister the platform_profile provider >> >> 2. When CnQF gets disabled restore the last set profile and >> register the platform_profile provider >> >> >> Questions/remarks: >> >> 1. If you look at 1. and 2. under "Probe time", you will see that >> when the BIOS requests to have CnQF enabled by default that >> userspace will then still shortly see a platform_profile >> provider. This must be fixed IMHO by checking whether to do >> CnQF by default or not before the initial register call. >> >> 2. What about low-power scenarios ? Currently power-profiles-daemon >> will always advertise a low-power mode even when there is no >> platform-profile support, since this is also a hint for other >> parts of the system to try and conserve power. But when this >> mode is enabled we really want the system to also behave as >> if the old static slider mode is active and set to low-power. >> >> Some ideas: >> a) maybe still have the amd-pmf code register a (different) >> platform_profile provider whn in CnQF mode and have it only >> advertise low-power >> >> b) teach power-profiles-daemon about CnQF and have it >> disable CnQF when entering low-power mode? >> >> c) make the CnQF code in PMF take the charge level into >> account and have it not go "full throttle" when the chare >> is below say 25% ? >> >> 3. Bastien, can power-profiles-daemon deal with >> /sys/firmware/acpi/platform_profile disappearing or >> appearing while it is running? > > No, it doesn't. > > It expects the platform_profile file to be available on startup, at > worse with the choices not yet filled in. It doesn't handle the > platform_profile file going away, it doesn't handle the > platform_profile_choices file changing after it's been initially > filled in, and it doesn't support less than one power profile being > made available, and only supports hiding the performance profile if > the platform doesn't support it. Ok, so this means that if we go with these changes as currently proposed that if a user uses the sysfs file to turn CnQF on/off they will need to restart power-profile-daemon. I think that that is acceptable given that the user needs to manually poke things anyway. We should probably document this in the documentation for the sysfs attribute (as well as in newer versions of the p-p-d docs/README). > Some of those things we could change/fix, some other things will not. > If the platform_profile_choices file only contained a single item, > then power-profiles-daemon would just export the "low-power" and > "balanced" profiles to user-space, as it does on unsupported hardware. Right. > The profiles in power-profiles-daemon are supposed to show the user > intent, which having a single setting would effectively nullify. Yes that was my understanding too. > It's unclear to me how CnQF takes user intent into account (it's also > unclear to me how that's a low-power setting rather than a combination > of the existing cool and quiet settings). AMD folks, please correct me if any of the below is wrong: AFAIK even though it is called CnQF it is more like auto-profile selection and as such does not take user intent into account at all. It looks at the workload over a somewhat longer time period (say 5 minutes or so I guess?) and then if that consistently has been quite high, it will select something similar to performance. Where as for a more mixed workload it will select balanced and for a mostly idle machine it will select low-power. I guess this auto feature is best treated the same as unsupported hw. > (it's also > unclear to me how that's a low-power setting rather than a combination > of the existing cool and quiet settings). Even though it is called cool and quiet AFAIK it won't be all that cool and quiet when running a heavy workload. Which is why I wonder how to re-conciliate this with showing low-power in e.g. the GNOME shell system men. Because in essence even if the battery is low the system will still go full-throttle when confronted with a heavy workload. So selecting low-power would result in the screen-dimming which I think is part of that, but the CPU's max power-consumption won't get limited as it would when platform-profiles are supported. So I guess this is indeed very much like how p-p-d behaves on unsupported hw... ### As mentioned I guess one option would be for CnQF to still register a platform_profile provider and then in balanced mode do its CnQF thing and in low-power mode disable CnQF and apply the static-slider low-power settings I think that that would work best from things actual working in a way I would expect the avarage end-user to expect things to work. So p-p-d would then still see platform-profile support in CnQF mode but with only low-power + balanced advertised. Bastien would that work for you? AMD folks would that also work for you ? ### I'm also wondering if we are going to still export balanced + low-power modes to userspace in CnQF mode and disable CnQF in low-power mode then if we even need a sysfs knob to turn it on/off at all. I guess the sysfs knob would then still be useful to turn it on on systems where it defaults to off in the BIOS. Might be better to do this as a kernel-cmdline (module-param) then though, then we also avoid the problem of platform_profile support all of a sudden changing underneath's p-p-d's feet. Regards, Hans and for toggling ooff through sysfs
On Thu, 1 Sept 2022 at 14:44, Hans de Goede <hdegoede@redhat.com> wrote: > > Hi, > > On 9/1/22 14:24, Bastien Nocera wrote: > > On Thu, 1 Sept 2022 at 13:16, Hans de Goede <hdegoede@redhat.com> wrote: > >> > >> Hi, > >> > >> On 8/23/22 12:29, Shyam Sundar S K wrote: > >>> In this series, support for following features has been added. > >>> - "Cool n Quiet Framework (CnQF)" is an extension to the static slider, > >>> where the system power can be boosted or throttled independent > >>> of the selected slider position. > >>> - On the fly, the CnQF can be turned on/off via a sysfs knob. > >> > >> Thank you. I think that before doing a more in detail review > >> we first need to agree on the userspace interactions here. > >> > >> I've added Bastien, the power-profiles-daemon maintainer > >> to the Cc for this. > >> > >> From a quick peek at the patches I see that currently they do > >> the following: > >> > >> Probe time: > >> ----------- > >> > >> 1. If static slider (classic /sys/firmware/acpi/platform_profile) > >> is available register as a platform_profile provider > >> > >> 2. Query if the BIOS tells us that CnQF should be enable by > >> default if yes then unregister the platform_profile provider > >> and enable CnQF > >> > >> > >> Run time: > >> --------- > >> > >> Allow turning CnQF on/off by writing a sysfs attribute for this. > >> > >> 1. When CnQF gets enabled unregister the platform_profile provider > >> > >> 2. When CnQF gets disabled restore the last set profile and > >> register the platform_profile provider > >> > >> > >> Questions/remarks: > >> > >> 1. If you look at 1. and 2. under "Probe time", you will see that > >> when the BIOS requests to have CnQF enabled by default that > >> userspace will then still shortly see a platform_profile > >> provider. This must be fixed IMHO by checking whether to do > >> CnQF by default or not before the initial register call. > >> > >> 2. What about low-power scenarios ? Currently power-profiles-daemon > >> will always advertise a low-power mode even when there is no > >> platform-profile support, since this is also a hint for other > >> parts of the system to try and conserve power. But when this > >> mode is enabled we really want the system to also behave as > >> if the old static slider mode is active and set to low-power. > >> > >> Some ideas: > >> a) maybe still have the amd-pmf code register a (different) > >> platform_profile provider whn in CnQF mode and have it only > >> advertise low-power > >> > >> b) teach power-profiles-daemon about CnQF and have it > >> disable CnQF when entering low-power mode? > >> > >> c) make the CnQF code in PMF take the charge level into > >> account and have it not go "full throttle" when the chare > >> is below say 25% ? > >> > >> 3. Bastien, can power-profiles-daemon deal with > >> /sys/firmware/acpi/platform_profile disappearing or > >> appearing while it is running? > > > > No, it doesn't. > > > > It expects the platform_profile file to be available on startup, at > > worse with the choices not yet filled in. It doesn't handle the > > platform_profile file going away, it doesn't handle the > > platform_profile_choices file changing after it's been initially > > filled in, and it doesn't support less than one power profile being > > made available, and only supports hiding the performance profile if > > the platform doesn't support it. > > Ok, so this means that if we go with these changes as currently > proposed that if a user uses the sysfs file to turn CnQF on/off > they will need to restart power-profile-daemon. > > I think that that is acceptable given that the user needs to manually > poke things anyway. We should probably document this in the documentation > for the sysfs attribute (as well as in newer versions of the p-p-d > docs/README). > > > Some of those things we could change/fix, some other things will not. > > If the platform_profile_choices file only contained a single item, > > then power-profiles-daemon would just export the "low-power" and > > "balanced" profiles to user-space, as it does on unsupported hardware. > > Right. > > > The profiles in power-profiles-daemon are supposed to show the user > > intent, which having a single setting would effectively nullify. > > Yes that was my understanding too. > > > It's unclear to me how CnQF takes user intent into account (it's also > > unclear to me how that's a low-power setting rather than a combination > > of the existing cool and quiet settings). > > AMD folks, please correct me if any of the below is wrong: > > AFAIK even though it is called CnQF it is more like auto-profile > selection and as such does not take user intent into account > at all. > > It looks at the workload over a somewhat longer time period (say > 5 minutes or so I guess?) and then if that consistently has been > quite high, it will select something similar to performance. > > Where as for a more mixed workload it will select balanced and for > a mostly idle machine it will select low-power. > > I guess this auto feature is best treated the same as unsupported hw. > > > (it's also > > unclear to me how that's a low-power setting rather than a combination > > of the existing cool and quiet settings). > > Even though it is called cool and quiet AFAIK it won't be all that > cool and quiet when running a heavy workload. Which is why I wonder > how to re-conciliate this with showing low-power in e.g. the > GNOME shell system men. Because in essence even if the battery > is low the system will still go full-throttle when confronted > with a heavy workload. > > So selecting low-power would result in the screen-dimming which > I think is part of that, but the CPU's max power-consumption won't > get limited as it would when platform-profiles are supported. > > So I guess this is indeed very much like how p-p-d behaves > on unsupported hw... > > ### > > As mentioned I guess one option would be for CnQF to > still register a platform_profile provider and then in > balanced mode do its CnQF thing and in low-power mode > disable CnQF and apply the static-slider low-power settings > I think that that would work best from things actual > working in a way I would expect the avarage end-user to > expect things to work. > > So p-p-d would then still see platform-profile support > in CnQF mode but with only low-power + balanced advertised. > > Bastien would that work for you? That's something I can make work, yes. > AMD folks would that also work for you ? > > ### > > I'm also wondering if we are going to still export > balanced + low-power modes to userspace in CnQF mode > and disable CnQF in low-power mode then if we > even need a sysfs knob to turn it on/off at all. > > I guess the sysfs knob would then still be useful > to turn it on on systems where it defaults to off > in the BIOS. Might be better to do this as > a kernel-cmdline (module-param) then though, then we > also avoid the problem of platform_profile support > all of a sudden changing underneath's p-p-d's feet. I would say that, you could probably have CnQF transparently replacing the more static "balanced" profile if it is available, and have a separate setting to force enable/disable it as a kernel command-line for debugging or if the BIOS menu doesn't offer it as an option. That way the balanced mode would work like a more refined automatic profile switcher, and make the default experience better, without the disappearing profiles, or the user-space API headaches.
Hi Hans, Apologies for the delay in responding to this thread. Some responses below. On 9/1/2022 6:14 PM, Hans de Goede wrote: > Hi, > > On 9/1/22 14:24, Bastien Nocera wrote: >> On Thu, 1 Sept 2022 at 13:16, Hans de Goede <hdegoede@redhat.com> wrote: >>> >>> Hi, >>> >>> On 8/23/22 12:29, Shyam Sundar S K wrote: >>>> In this series, support for following features has been added. >>>> - "Cool n Quiet Framework (CnQF)" is an extension to the static slider, >>>> where the system power can be boosted or throttled independent >>>> of the selected slider position. >>>> - On the fly, the CnQF can be turned on/off via a sysfs knob. >>> >>> Thank you. I think that before doing a more in detail review >>> we first need to agree on the userspace interactions here. >>> >>> I've added Bastien, the power-profiles-daemon maintainer >>> to the Cc for this. >>> >>> From a quick peek at the patches I see that currently they do >>> the following: >>> >>> Probe time: >>> ----------- >>> >>> 1. If static slider (classic /sys/firmware/acpi/platform_profile) >>> is available register as a platform_profile provider >>> >>> 2. Query if the BIOS tells us that CnQF should be enable by >>> default if yes then unregister the platform_profile provider >>> and enable CnQF >>> >>> >>> Run time: >>> --------- >>> >>> Allow turning CnQF on/off by writing a sysfs attribute for this. >>> >>> 1. When CnQF gets enabled unregister the platform_profile provider >>> >>> 2. When CnQF gets disabled restore the last set profile and >>> register the platform_profile provider >>> >>> >>> Questions/remarks: >>> >>> 1. If you look at 1. and 2. under "Probe time", you will see that >>> when the BIOS requests to have CnQF enabled by default that >>> userspace will then still shortly see a platform_profile >>> provider. This must be fixed IMHO by checking whether to do >>> CnQF by default or not before the initial register call. >>> >>> 2. What about low-power scenarios ? Currently power-profiles-daemon >>> will always advertise a low-power mode even when there is no >>> platform-profile support, since this is also a hint for other >>> parts of the system to try and conserve power. But when this >>> mode is enabled we really want the system to also behave as >>> if the old static slider mode is active and set to low-power. >>> >>> Some ideas: >>> a) maybe still have the amd-pmf code register a (different) >>> platform_profile provider whn in CnQF mode and have it only >>> advertise low-power >>> >>> b) teach power-profiles-daemon about CnQF and have it >>> disable CnQF when entering low-power mode? >>> >>> c) make the CnQF code in PMF take the charge level into >>> account and have it not go "full throttle" when the chare >>> is below say 25% ? >>> >>> 3. Bastien, can power-profiles-daemon deal with >>> /sys/firmware/acpi/platform_profile disappearing or >>> appearing while it is running? >> >> No, it doesn't. >> >> It expects the platform_profile file to be available on startup, at >> worse with the choices not yet filled in. It doesn't handle the >> platform_profile file going away, it doesn't handle the >> platform_profile_choices file changing after it's been initially >> filled in, and it doesn't support less than one power profile being >> made available, and only supports hiding the performance profile if >> the platform doesn't support it. > > Ok, so this means that if we go with these changes as currently > proposed that if a user uses the sysfs file to turn CnQF on/off > they will need to restart power-profile-daemon. > > I think that that is acceptable given that the user needs to manually > poke things anyway. We should probably document this in the documentation > for the sysfs attribute (as well as in newer versions of the p-p-d > docs/README). > >> Some of those things we could change/fix, some other things will not. >> If the platform_profile_choices file only contained a single item, >> then power-profiles-daemon would just export the "low-power" and >> "balanced" profiles to user-space, as it does on unsupported hardware. > > Right. > >> The profiles in power-profiles-daemon are supposed to show the user >> intent, which having a single setting would effectively nullify. > > Yes that was my understanding too. > >> It's unclear to me how CnQF takes user intent into account (it's also >> unclear to me how that's a low-power setting rather than a combination >> of the existing cool and quiet settings). > > AMD folks, please correct me if any of the below is wrong: > > AFAIK even though it is called CnQF it is more like auto-profile > selection and as such does not take user intent into account > at all. Yes, You are right. Below is a brief note on how CnQF was designed. 1)CnQF – Cool And Quiet Framework - It’s an extension of the static slider concept wherein PMF dynamically manages system power limits and fan policy based on system power trends. 2)OEM can opt into the feature by defining the CnQF BIOS ACPI method. 3)Static slider control and CnQF are mutually exclusive. 4)CnQF supports up to 4 modes of operation – Turbo, Performance, Balanced and Quiet. - It can be configured for AC and DC distinctly. - PMF driver calculates the moving average of system power and switches the mode of operation. *If system power is limited to the threshold of the current mode, move to the next higher mode *If system power is not limited to the threshold of the current mode, reduce the power budget by moving to the next lower mode. 5)CnQF feature control is through Radeon SW (a GUI based tool on Windows) To match the behavior on Windows, we kept a sysfs node to turn on/off the CnQF on the fly like the way it can be done the windows side with the Radeon SW tool. If you think that having as a module param makes more sense, I am open to make the change and send a v2. Like I mentioned above, on Windows the static slider is absoultely dummy when the user goes on turns on the CnQF from Radeon SW tool. Based on the review remarks on the earlier series, we tried to register/de-register to platform_profile, as per sysfs input (like setting up and tearing down to platform_profile). The Difference between Auto-mode (for thinkpads) and CnQF(for others) is that: - Automode gets turned on only when the slider position is set to "balanced" in the platform_profile and - a corresponding AMT ON event is triggered. - it has 3 internal modes quiet, balanced, performance But for CnQF, - it is independent of the slider position and there are no ACPI events for it to get kicked in. - There are two seperate ACPI methods for AC and DC to get the corresponding thermal values. - it has 4 internal modes quiet, balanced, performance, turbo There is already a WIP feature called "policy builder" where the OEMs can build custom policies, which includes looking at the battery percentages and making thermal optimizations accordingly. But this was not taken into consideration while designing the CnQF on windows too. If we bring in this change for Linux, there maybe differences in the way the same feature behaves "differently" across OSes. Like you mentioned the usecase, where just a compilation can end up in battery drain if not connected to AC power. Can we not have a documentation update saying it is advised to turn "off" CnQF when battery % goes below a certain level? That way, the end user experiences across Linux and Windows remains the same. > > It looks at the workload over a somewhat longer time period (say > 5 minutes or so I guess?) and then if that consistently has been > quite high, it will select something similar to performance. Right. The switch time would be dependent on the "time constant" values set in the BIOS which is configurable to the OEMs. > > Where as for a more mixed workload it will select balanced and for > a mostly idle machine it will select low-power. > > I guess this auto feature is best treated the same as unsupported hw. > >> (it's also >> unclear to me how that's a low-power setting rather than a combination >> of the existing cool and quiet settings). > > Even though it is called cool and quiet AFAIK it won't be all that > cool and quiet when running a heavy workload. Which is why I wonder > how to re-conciliate this with showing low-power in e.g. the > GNOME shell system men. Because in essence even if the battery > is low the system will still go full-throttle when confronted > with a heavy workload. > > So selecting low-power would result in the screen-dimming which > I think is part of that, but the CPU's max power-consumption won't > get limited as it would when platform-profiles are supported. > > So I guess this is indeed very much like how p-p-d behaves > on unsupported hw... > > ### > > As mentioned I guess one option would be for CnQF to > still register a platform_profile provider and then in > balanced mode do its CnQF thing and in low-power mode > disable CnQF and apply the static-slider low-power settings > I think that that would work best from things actual > working in a way I would expect the avarage end-user to > expect things to work. > > So p-p-d would then still see platform-profile support > in CnQF mode but with only low-power + balanced advertised. > > Bastien would that work for you? > > AMD folks would that also work for you ? If we go with the above proposal it would become very identical to what is being done with automode (expect the extra "turbo" mode and not having a AMT event). This would need some amount of discussion with our windows folks also to know what they think about it. Please let me know your thoughts based on the above notes what I provided(in the earlier section), so that we can make the code changes accordingly. Thanks, Shyam > > ### > > I'm also wondering if we are going to still export > balanced + low-power modes to userspace in CnQF mode > and disable CnQF in low-power mode then if we > even need a sysfs knob to turn it on/off at all. > > I guess the sysfs knob would then still be useful > to turn it on on systems where it defaults to off > in the BIOS. Might be better to do this as > a kernel-cmdline (module-param) then though, then we > also avoid the problem of platform_profile support > all of a sudden changing underneath's p-p-d's feet. > > Regards, > > Hans > > > > > > > and for toggling ooff through sysfs >
Hi Bastien, Hans On 9/1/2022 7:04 PM, Bastien Nocera wrote: > On Thu, 1 Sept 2022 at 14:44, Hans de Goede <hdegoede@redhat.com> wrote: >> >> Hi, >> >> On 9/1/22 14:24, Bastien Nocera wrote: >>> On Thu, 1 Sept 2022 at 13:16, Hans de Goede <hdegoede@redhat.com> wrote: >>>> >>>> Hi, >>>> >>>> On 8/23/22 12:29, Shyam Sundar S K wrote: >>>>> In this series, support for following features has been added. >>>>> - "Cool n Quiet Framework (CnQF)" is an extension to the static slider, >>>>> where the system power can be boosted or throttled independent >>>>> of the selected slider position. >>>>> - On the fly, the CnQF can be turned on/off via a sysfs knob. >>>> >>>> Thank you. I think that before doing a more in detail review >>>> we first need to agree on the userspace interactions here. >>>> >>>> I've added Bastien, the power-profiles-daemon maintainer >>>> to the Cc for this. >>>> >>>> From a quick peek at the patches I see that currently they do >>>> the following: >>>> >>>> Probe time: >>>> ----------- >>>> >>>> 1. If static slider (classic /sys/firmware/acpi/platform_profile) >>>> is available register as a platform_profile provider >>>> >>>> 2. Query if the BIOS tells us that CnQF should be enable by >>>> default if yes then unregister the platform_profile provider >>>> and enable CnQF >>>> >>>> >>>> Run time: >>>> --------- >>>> >>>> Allow turning CnQF on/off by writing a sysfs attribute for this. >>>> >>>> 1. When CnQF gets enabled unregister the platform_profile provider >>>> >>>> 2. When CnQF gets disabled restore the last set profile and >>>> register the platform_profile provider >>>> >>>> >>>> Questions/remarks: >>>> >>>> 1. If you look at 1. and 2. under "Probe time", you will see that >>>> when the BIOS requests to have CnQF enabled by default that >>>> userspace will then still shortly see a platform_profile >>>> provider. This must be fixed IMHO by checking whether to do >>>> CnQF by default or not before the initial register call. >>>> >>>> 2. What about low-power scenarios ? Currently power-profiles-daemon >>>> will always advertise a low-power mode even when there is no >>>> platform-profile support, since this is also a hint for other >>>> parts of the system to try and conserve power. But when this >>>> mode is enabled we really want the system to also behave as >>>> if the old static slider mode is active and set to low-power. >>>> >>>> Some ideas: >>>> a) maybe still have the amd-pmf code register a (different) >>>> platform_profile provider whn in CnQF mode and have it only >>>> advertise low-power >>>> >>>> b) teach power-profiles-daemon about CnQF and have it >>>> disable CnQF when entering low-power mode? >>>> >>>> c) make the CnQF code in PMF take the charge level into >>>> account and have it not go "full throttle" when the chare >>>> is below say 25% ? >>>> >>>> 3. Bastien, can power-profiles-daemon deal with >>>> /sys/firmware/acpi/platform_profile disappearing or >>>> appearing while it is running? >>> >>> No, it doesn't. >>> >>> It expects the platform_profile file to be available on startup, at >>> worse with the choices not yet filled in. It doesn't handle the >>> platform_profile file going away, it doesn't handle the >>> platform_profile_choices file changing after it's been initially >>> filled in, and it doesn't support less than one power profile being >>> made available, and only supports hiding the performance profile if >>> the platform doesn't support it. >> >> Ok, so this means that if we go with these changes as currently >> proposed that if a user uses the sysfs file to turn CnQF on/off >> they will need to restart power-profile-daemon. >> >> I think that that is acceptable given that the user needs to manually >> poke things anyway. We should probably document this in the documentation >> for the sysfs attribute (as well as in newer versions of the p-p-d >> docs/README). >> >>> Some of those things we could change/fix, some other things will not. >>> If the platform_profile_choices file only contained a single item, >>> then power-profiles-daemon would just export the "low-power" and >>> "balanced" profiles to user-space, as it does on unsupported hardware. >> >> Right. >> >>> The profiles in power-profiles-daemon are supposed to show the user >>> intent, which having a single setting would effectively nullify. >> >> Yes that was my understanding too. >> >>> It's unclear to me how CnQF takes user intent into account (it's also >>> unclear to me how that's a low-power setting rather than a combination >>> of the existing cool and quiet settings). >> >> AMD folks, please correct me if any of the below is wrong: >> >> AFAIK even though it is called CnQF it is more like auto-profile >> selection and as such does not take user intent into account >> at all. >> >> It looks at the workload over a somewhat longer time period (say >> 5 minutes or so I guess?) and then if that consistently has been >> quite high, it will select something similar to performance. >> >> Where as for a more mixed workload it will select balanced and for >> a mostly idle machine it will select low-power. >> >> I guess this auto feature is best treated the same as unsupported hw. >> >>> (it's also >>> unclear to me how that's a low-power setting rather than a combination >>> of the existing cool and quiet settings). >> >> Even though it is called cool and quiet AFAIK it won't be all that >> cool and quiet when running a heavy workload. Which is why I wonder >> how to re-conciliate this with showing low-power in e.g. the >> GNOME shell system men. Because in essence even if the battery >> is low the system will still go full-throttle when confronted >> with a heavy workload. >> >> So selecting low-power would result in the screen-dimming which >> I think is part of that, but the CPU's max power-consumption won't >> get limited as it would when platform-profiles are supported. >> >> So I guess this is indeed very much like how p-p-d behaves >> on unsupported hw... >> >> ### >> >> As mentioned I guess one option would be for CnQF to >> still register a platform_profile provider and then in >> balanced mode do its CnQF thing and in low-power mode >> disable CnQF and apply the static-slider low-power settings >> I think that that would work best from things actual >> working in a way I would expect the avarage end-user to >> expect things to work. >> >> So p-p-d would then still see platform-profile support >> in CnQF mode but with only low-power + balanced advertised. >> >> Bastien would that work for you? > > That's something I can make work, yes. > >> AMD folks would that also work for you ? >> >> ### >> >> I'm also wondering if we are going to still export >> balanced + low-power modes to userspace in CnQF mode >> and disable CnQF in low-power mode then if we >> even need a sysfs knob to turn it on/off at all. >> >> I guess the sysfs knob would then still be useful >> to turn it on on systems where it defaults to off >> in the BIOS. Might be better to do this as >> a kernel-cmdline (module-param) then though, then we >> also avoid the problem of platform_profile support >> all of a sudden changing underneath's p-p-d's feet. > > I would say that, you could probably have CnQF transparently replacing > the more static "balanced" profile if it is available, and have a > separate setting to force enable/disable it as a kernel command-line > for debugging or if the BIOS menu doesn't offer it as an option. > > That way the balanced mode would work like a more refined automatic > profile switcher, and make the default experience better, without the > disappearing profiles, or the user-space API headaches. > module param would be fine to force load CnQF if the BIOS does not advertise it. But I still think, having a sysfs node would still help to give an option to the user to "opt-out" of the scenarios where he thinks that battery can drain out if CnQF is turned on? Or in any case to turn on/off CnQF on the fly, so that he can still switch back to the traditional "static slider" based power optimizations. Please let me know your thoughts on this? Thanks, Shyam
Hey Shyam, I misunderstood that CnQF was a single setting, but it looks like it has 4 different levels, right? Unless there's a major malfunction, I don't think that offering to switch between 2 different policies where the difference is how "static" the performance boosts are is very useful, or comprehensible, to end-users. If CnQF only has a single "on" setting, then this could replace the balanced mode for what you call "static slider", so the end-user can still make a choice and have agency on whether the system tries to save power, or increase performance. If CnQF has multiple levels (Turbo, Performance, Balanced and Quiet, right?), then I don't think it's useful to have a sysfs setting to switch it at runtime, which only confuses user-space and the users. BIOS setting and/or kernel command-line option are the way to go. Did I understand this correctly? On Tue, 6 Sept 2022 at 12:00, Shyam Sundar S K <Shyam-sundar.S-k@amd.com> wrote: > > Hi Bastien, Hans > > On 9/1/2022 7:04 PM, Bastien Nocera wrote: > > On Thu, 1 Sept 2022 at 14:44, Hans de Goede <hdegoede@redhat.com> wrote: > >> > >> Hi, > >> > >> On 9/1/22 14:24, Bastien Nocera wrote: > >>> On Thu, 1 Sept 2022 at 13:16, Hans de Goede <hdegoede@redhat.com> wrote: > >>>> > >>>> Hi, > >>>> > >>>> On 8/23/22 12:29, Shyam Sundar S K wrote: > >>>>> In this series, support for following features has been added. > >>>>> - "Cool n Quiet Framework (CnQF)" is an extension to the static slider, > >>>>> where the system power can be boosted or throttled independent > >>>>> of the selected slider position. > >>>>> - On the fly, the CnQF can be turned on/off via a sysfs knob. > >>>> > >>>> Thank you. I think that before doing a more in detail review > >>>> we first need to agree on the userspace interactions here. > >>>> > >>>> I've added Bastien, the power-profiles-daemon maintainer > >>>> to the Cc for this. > >>>> > >>>> From a quick peek at the patches I see that currently they do > >>>> the following: > >>>> > >>>> Probe time: > >>>> ----------- > >>>> > >>>> 1. If static slider (classic /sys/firmware/acpi/platform_profile) > >>>> is available register as a platform_profile provider > >>>> > >>>> 2. Query if the BIOS tells us that CnQF should be enable by > >>>> default if yes then unregister the platform_profile provider > >>>> and enable CnQF > >>>> > >>>> > >>>> Run time: > >>>> --------- > >>>> > >>>> Allow turning CnQF on/off by writing a sysfs attribute for this. > >>>> > >>>> 1. When CnQF gets enabled unregister the platform_profile provider > >>>> > >>>> 2. When CnQF gets disabled restore the last set profile and > >>>> register the platform_profile provider > >>>> > >>>> > >>>> Questions/remarks: > >>>> > >>>> 1. If you look at 1. and 2. under "Probe time", you will see that > >>>> when the BIOS requests to have CnQF enabled by default that > >>>> userspace will then still shortly see a platform_profile > >>>> provider. This must be fixed IMHO by checking whether to do > >>>> CnQF by default or not before the initial register call. > >>>> > >>>> 2. What about low-power scenarios ? Currently power-profiles-daemon > >>>> will always advertise a low-power mode even when there is no > >>>> platform-profile support, since this is also a hint for other > >>>> parts of the system to try and conserve power. But when this > >>>> mode is enabled we really want the system to also behave as > >>>> if the old static slider mode is active and set to low-power. > >>>> > >>>> Some ideas: > >>>> a) maybe still have the amd-pmf code register a (different) > >>>> platform_profile provider whn in CnQF mode and have it only > >>>> advertise low-power > >>>> > >>>> b) teach power-profiles-daemon about CnQF and have it > >>>> disable CnQF when entering low-power mode? > >>>> > >>>> c) make the CnQF code in PMF take the charge level into > >>>> account and have it not go "full throttle" when the chare > >>>> is below say 25% ? > >>>> > >>>> 3. Bastien, can power-profiles-daemon deal with > >>>> /sys/firmware/acpi/platform_profile disappearing or > >>>> appearing while it is running? > >>> > >>> No, it doesn't. > >>> > >>> It expects the platform_profile file to be available on startup, at > >>> worse with the choices not yet filled in. It doesn't handle the > >>> platform_profile file going away, it doesn't handle the > >>> platform_profile_choices file changing after it's been initially > >>> filled in, and it doesn't support less than one power profile being > >>> made available, and only supports hiding the performance profile if > >>> the platform doesn't support it. > >> > >> Ok, so this means that if we go with these changes as currently > >> proposed that if a user uses the sysfs file to turn CnQF on/off > >> they will need to restart power-profile-daemon. > >> > >> I think that that is acceptable given that the user needs to manually > >> poke things anyway. We should probably document this in the documentation > >> for the sysfs attribute (as well as in newer versions of the p-p-d > >> docs/README). > >> > >>> Some of those things we could change/fix, some other things will not. > >>> If the platform_profile_choices file only contained a single item, > >>> then power-profiles-daemon would just export the "low-power" and > >>> "balanced" profiles to user-space, as it does on unsupported hardware. > >> > >> Right. > >> > >>> The profiles in power-profiles-daemon are supposed to show the user > >>> intent, which having a single setting would effectively nullify. > >> > >> Yes that was my understanding too. > >> > >>> It's unclear to me how CnQF takes user intent into account (it's also > >>> unclear to me how that's a low-power setting rather than a combination > >>> of the existing cool and quiet settings). > >> > >> AMD folks, please correct me if any of the below is wrong: > >> > >> AFAIK even though it is called CnQF it is more like auto-profile > >> selection and as such does not take user intent into account > >> at all. > >> > >> It looks at the workload over a somewhat longer time period (say > >> 5 minutes or so I guess?) and then if that consistently has been > >> quite high, it will select something similar to performance. > >> > >> Where as for a more mixed workload it will select balanced and for > >> a mostly idle machine it will select low-power. > >> > >> I guess this auto feature is best treated the same as unsupported hw. > >> > >>> (it's also > >>> unclear to me how that's a low-power setting rather than a combination > >>> of the existing cool and quiet settings). > >> > >> Even though it is called cool and quiet AFAIK it won't be all that > >> cool and quiet when running a heavy workload. Which is why I wonder > >> how to re-conciliate this with showing low-power in e.g. the > >> GNOME shell system men. Because in essence even if the battery > >> is low the system will still go full-throttle when confronted > >> with a heavy workload. > >> > >> So selecting low-power would result in the screen-dimming which > >> I think is part of that, but the CPU's max power-consumption won't > >> get limited as it would when platform-profiles are supported. > >> > >> So I guess this is indeed very much like how p-p-d behaves > >> on unsupported hw... > >> > >> ### > >> > >> As mentioned I guess one option would be for CnQF to > >> still register a platform_profile provider and then in > >> balanced mode do its CnQF thing and in low-power mode > >> disable CnQF and apply the static-slider low-power settings > >> I think that that would work best from things actual > >> working in a way I would expect the avarage end-user to > >> expect things to work. > >> > >> So p-p-d would then still see platform-profile support > >> in CnQF mode but with only low-power + balanced advertised. > >> > >> Bastien would that work for you? > > > > That's something I can make work, yes. > > > >> AMD folks would that also work for you ? > >> > >> ### > >> > >> I'm also wondering if we are going to still export > >> balanced + low-power modes to userspace in CnQF mode > >> and disable CnQF in low-power mode then if we > >> even need a sysfs knob to turn it on/off at all. > >> > >> I guess the sysfs knob would then still be useful > >> to turn it on on systems where it defaults to off > >> in the BIOS. Might be better to do this as > >> a kernel-cmdline (module-param) then though, then we > >> also avoid the problem of platform_profile support > >> all of a sudden changing underneath's p-p-d's feet. > > > > I would say that, you could probably have CnQF transparently replacing > > the more static "balanced" profile if it is available, and have a > > separate setting to force enable/disable it as a kernel command-line > > for debugging or if the BIOS menu doesn't offer it as an option. > > > > That way the balanced mode would work like a more refined automatic > > profile switcher, and make the default experience better, without the > > disappearing profiles, or the user-space API headaches. > > > > module param would be fine to force load CnQF if the BIOS does not > advertise it. > > But I still think, having a sysfs node would still help to give an > option to the user to "opt-out" of the scenarios where he thinks that > battery can drain out if CnQF is turned on? Or in any case to turn > on/off CnQF on the fly, so that he can still switch back to the > traditional "static slider" based power optimizations. > > Please let me know your thoughts on this? > > Thanks, > Shyam >
Hi Bastien, On 9/7/22 16:24, Bastien Nocera wrote: > Hey Shyam, > > I misunderstood that CnQF was a single setting, but it looks like it > has 4 different levels, right? > Unless there's a major malfunction, I don't think that offering to > switch between 2 different policies where the difference is how > "static" the performance boosts are is very useful, or comprehensible, > to end-users. > > If CnQF only has a single "on" setting, then this could replace the > balanced mode for what you call "static slider", so the end-user can > still make a choice and have agency on whether the system tries to > save power, or increase performance. > > If CnQF has multiple levels (Turbo, Performance, Balanced and Quiet, > right?), then I don't think it's useful to have a sysfs setting to > switch it at runtime, which only confuses user-space and the users. > BIOS setting and/or kernel command-line option are the way to go. > > Did I understand this correctly? Let me try clarify things: CnQF has 4 levels internally, between which it switches automatically based on the workload of the last 5 minutes. So from a userspace pov CnQF is a single setting which can be toggled on / off. Basically it is a more dynamic balanced mode, so I think it makes sense for the amd-pmf code to always export a platform_profile interface and when CnQF is on then use CnQF for balanced and the static slider settings for low-power / performance. And when CnQF is off, then just use what AMD calls the static slider balanced setting. This way for performance-profile-daemon nothing really changes. This can then be combined with allowing the user to turn CnQF on/off through sysfs as an extra option which p-p-d can ignore (this sysfs file then choses between CnQF and static balanced mode when balance is set through the platform interface). Regards, Hans p.s. Shyam I will reply to your emails in a couple of minutes. > > On Tue, 6 Sept 2022 at 12:00, Shyam Sundar S K <Shyam-sundar.S-k@amd.com> wrote: >> >> Hi Bastien, Hans >> >> On 9/1/2022 7:04 PM, Bastien Nocera wrote: >>> On Thu, 1 Sept 2022 at 14:44, Hans de Goede <hdegoede@redhat.com> wrote: >>>> >>>> Hi, >>>> >>>> On 9/1/22 14:24, Bastien Nocera wrote: >>>>> On Thu, 1 Sept 2022 at 13:16, Hans de Goede <hdegoede@redhat.com> wrote: >>>>>> >>>>>> Hi, >>>>>> >>>>>> On 8/23/22 12:29, Shyam Sundar S K wrote: >>>>>>> In this series, support for following features has been added. >>>>>>> - "Cool n Quiet Framework (CnQF)" is an extension to the static slider, >>>>>>> where the system power can be boosted or throttled independent >>>>>>> of the selected slider position. >>>>>>> - On the fly, the CnQF can be turned on/off via a sysfs knob. >>>>>> >>>>>> Thank you. I think that before doing a more in detail review >>>>>> we first need to agree on the userspace interactions here. >>>>>> >>>>>> I've added Bastien, the power-profiles-daemon maintainer >>>>>> to the Cc for this. >>>>>> >>>>>> From a quick peek at the patches I see that currently they do >>>>>> the following: >>>>>> >>>>>> Probe time: >>>>>> ----------- >>>>>> >>>>>> 1. If static slider (classic /sys/firmware/acpi/platform_profile) >>>>>> is available register as a platform_profile provider >>>>>> >>>>>> 2. Query if the BIOS tells us that CnQF should be enable by >>>>>> default if yes then unregister the platform_profile provider >>>>>> and enable CnQF >>>>>> >>>>>> >>>>>> Run time: >>>>>> --------- >>>>>> >>>>>> Allow turning CnQF on/off by writing a sysfs attribute for this. >>>>>> >>>>>> 1. When CnQF gets enabled unregister the platform_profile provider >>>>>> >>>>>> 2. When CnQF gets disabled restore the last set profile and >>>>>> register the platform_profile provider >>>>>> >>>>>> >>>>>> Questions/remarks: >>>>>> >>>>>> 1. If you look at 1. and 2. under "Probe time", you will see that >>>>>> when the BIOS requests to have CnQF enabled by default that >>>>>> userspace will then still shortly see a platform_profile >>>>>> provider. This must be fixed IMHO by checking whether to do >>>>>> CnQF by default or not before the initial register call. >>>>>> >>>>>> 2. What about low-power scenarios ? Currently power-profiles-daemon >>>>>> will always advertise a low-power mode even when there is no >>>>>> platform-profile support, since this is also a hint for other >>>>>> parts of the system to try and conserve power. But when this >>>>>> mode is enabled we really want the system to also behave as >>>>>> if the old static slider mode is active and set to low-power. >>>>>> >>>>>> Some ideas: >>>>>> a) maybe still have the amd-pmf code register a (different) >>>>>> platform_profile provider whn in CnQF mode and have it only >>>>>> advertise low-power >>>>>> >>>>>> b) teach power-profiles-daemon about CnQF and have it >>>>>> disable CnQF when entering low-power mode? >>>>>> >>>>>> c) make the CnQF code in PMF take the charge level into >>>>>> account and have it not go "full throttle" when the chare >>>>>> is below say 25% ? >>>>>> >>>>>> 3. Bastien, can power-profiles-daemon deal with >>>>>> /sys/firmware/acpi/platform_profile disappearing or >>>>>> appearing while it is running? >>>>> >>>>> No, it doesn't. >>>>> >>>>> It expects the platform_profile file to be available on startup, at >>>>> worse with the choices not yet filled in. It doesn't handle the >>>>> platform_profile file going away, it doesn't handle the >>>>> platform_profile_choices file changing after it's been initially >>>>> filled in, and it doesn't support less than one power profile being >>>>> made available, and only supports hiding the performance profile if >>>>> the platform doesn't support it. >>>> >>>> Ok, so this means that if we go with these changes as currently >>>> proposed that if a user uses the sysfs file to turn CnQF on/off >>>> they will need to restart power-profile-daemon. >>>> >>>> I think that that is acceptable given that the user needs to manually >>>> poke things anyway. We should probably document this in the documentation >>>> for the sysfs attribute (as well as in newer versions of the p-p-d >>>> docs/README). >>>> >>>>> Some of those things we could change/fix, some other things will not. >>>>> If the platform_profile_choices file only contained a single item, >>>>> then power-profiles-daemon would just export the "low-power" and >>>>> "balanced" profiles to user-space, as it does on unsupported hardware. >>>> >>>> Right. >>>> >>>>> The profiles in power-profiles-daemon are supposed to show the user >>>>> intent, which having a single setting would effectively nullify. >>>> >>>> Yes that was my understanding too. >>>> >>>>> It's unclear to me how CnQF takes user intent into account (it's also >>>>> unclear to me how that's a low-power setting rather than a combination >>>>> of the existing cool and quiet settings). >>>> >>>> AMD folks, please correct me if any of the below is wrong: >>>> >>>> AFAIK even though it is called CnQF it is more like auto-profile >>>> selection and as such does not take user intent into account >>>> at all. >>>> >>>> It looks at the workload over a somewhat longer time period (say >>>> 5 minutes or so I guess?) and then if that consistently has been >>>> quite high, it will select something similar to performance. >>>> >>>> Where as for a more mixed workload it will select balanced and for >>>> a mostly idle machine it will select low-power. >>>> >>>> I guess this auto feature is best treated the same as unsupported hw. >>>> >>>>> (it's also >>>>> unclear to me how that's a low-power setting rather than a combination >>>>> of the existing cool and quiet settings). >>>> >>>> Even though it is called cool and quiet AFAIK it won't be all that >>>> cool and quiet when running a heavy workload. Which is why I wonder >>>> how to re-conciliate this with showing low-power in e.g. the >>>> GNOME shell system men. Because in essence even if the battery >>>> is low the system will still go full-throttle when confronted >>>> with a heavy workload. >>>> >>>> So selecting low-power would result in the screen-dimming which >>>> I think is part of that, but the CPU's max power-consumption won't >>>> get limited as it would when platform-profiles are supported. >>>> >>>> So I guess this is indeed very much like how p-p-d behaves >>>> on unsupported hw... >>>> >>>> ### >>>> >>>> As mentioned I guess one option would be for CnQF to >>>> still register a platform_profile provider and then in >>>> balanced mode do its CnQF thing and in low-power mode >>>> disable CnQF and apply the static-slider low-power settings >>>> I think that that would work best from things actual >>>> working in a way I would expect the avarage end-user to >>>> expect things to work. >>>> >>>> So p-p-d would then still see platform-profile support >>>> in CnQF mode but with only low-power + balanced advertised. >>>> >>>> Bastien would that work for you? >>> >>> That's something I can make work, yes. >>> >>>> AMD folks would that also work for you ? >>>> >>>> ### >>>> >>>> I'm also wondering if we are going to still export >>>> balanced + low-power modes to userspace in CnQF mode >>>> and disable CnQF in low-power mode then if we >>>> even need a sysfs knob to turn it on/off at all. >>>> >>>> I guess the sysfs knob would then still be useful >>>> to turn it on on systems where it defaults to off >>>> in the BIOS. Might be better to do this as >>>> a kernel-cmdline (module-param) then though, then we >>>> also avoid the problem of platform_profile support >>>> all of a sudden changing underneath's p-p-d's feet. >>> >>> I would say that, you could probably have CnQF transparently replacing >>> the more static "balanced" profile if it is available, and have a >>> separate setting to force enable/disable it as a kernel command-line >>> for debugging or if the BIOS menu doesn't offer it as an option. >>> >>> That way the balanced mode would work like a more refined automatic >>> profile switcher, and make the default experience better, without the >>> disappearing profiles, or the user-space API headaches. >>> >> >> module param would be fine to force load CnQF if the BIOS does not >> advertise it. >> >> But I still think, having a sysfs node would still help to give an >> option to the user to "opt-out" of the scenarios where he thinks that >> battery can drain out if CnQF is turned on? Or in any case to turn >> on/off CnQF on the fly, so that he can still switch back to the >> traditional "static slider" based power optimizations. >> >> Please let me know your thoughts on this? >> >> Thanks, >> Shyam >> >
Hi, On 9/6/22 11:53, Shyam Sundar S K wrote: > Hi Hans, > > Apologies for the delay in responding to this thread. Some responses below. No worries. > On 9/1/2022 6:14 PM, Hans de Goede wrote: >> Hi, >> >> On 9/1/22 14:24, Bastien Nocera wrote: >>> On Thu, 1 Sept 2022 at 13:16, Hans de Goede <hdegoede@redhat.com> wrote: >>>> >>>> Hi, >>>> >>>> On 8/23/22 12:29, Shyam Sundar S K wrote: >>>>> In this series, support for following features has been added. >>>>> - "Cool n Quiet Framework (CnQF)" is an extension to the static slider, >>>>> where the system power can be boosted or throttled independent >>>>> of the selected slider position. >>>>> - On the fly, the CnQF can be turned on/off via a sysfs knob. >>>> >>>> Thank you. I think that before doing a more in detail review >>>> we first need to agree on the userspace interactions here. >>>> >>>> I've added Bastien, the power-profiles-daemon maintainer >>>> to the Cc for this. >>>> >>>> From a quick peek at the patches I see that currently they do >>>> the following: >>>> >>>> Probe time: >>>> ----------- >>>> >>>> 1. If static slider (classic /sys/firmware/acpi/platform_profile) >>>> is available register as a platform_profile provider >>>> >>>> 2. Query if the BIOS tells us that CnQF should be enable by >>>> default if yes then unregister the platform_profile provider >>>> and enable CnQF >>>> >>>> >>>> Run time: >>>> --------- >>>> >>>> Allow turning CnQF on/off by writing a sysfs attribute for this. >>>> >>>> 1. When CnQF gets enabled unregister the platform_profile provider >>>> >>>> 2. When CnQF gets disabled restore the last set profile and >>>> register the platform_profile provider >>>> >>>> >>>> Questions/remarks: >>>> >>>> 1. If you look at 1. and 2. under "Probe time", you will see that >>>> when the BIOS requests to have CnQF enabled by default that >>>> userspace will then still shortly see a platform_profile >>>> provider. This must be fixed IMHO by checking whether to do >>>> CnQF by default or not before the initial register call. >>>> >>>> 2. What about low-power scenarios ? Currently power-profiles-daemon >>>> will always advertise a low-power mode even when there is no >>>> platform-profile support, since this is also a hint for other >>>> parts of the system to try and conserve power. But when this >>>> mode is enabled we really want the system to also behave as >>>> if the old static slider mode is active and set to low-power. >>>> >>>> Some ideas: >>>> a) maybe still have the amd-pmf code register a (different) >>>> platform_profile provider whn in CnQF mode and have it only >>>> advertise low-power >>>> >>>> b) teach power-profiles-daemon about CnQF and have it >>>> disable CnQF when entering low-power mode? >>>> >>>> c) make the CnQF code in PMF take the charge level into >>>> account and have it not go "full throttle" when the chare >>>> is below say 25% ? >>>> >>>> 3. Bastien, can power-profiles-daemon deal with >>>> /sys/firmware/acpi/platform_profile disappearing or >>>> appearing while it is running? >>> >>> No, it doesn't. >>> >>> It expects the platform_profile file to be available on startup, at >>> worse with the choices not yet filled in. It doesn't handle the >>> platform_profile file going away, it doesn't handle the >>> platform_profile_choices file changing after it's been initially >>> filled in, and it doesn't support less than one power profile being >>> made available, and only supports hiding the performance profile if >>> the platform doesn't support it. >> >> Ok, so this means that if we go with these changes as currently >> proposed that if a user uses the sysfs file to turn CnQF on/off >> they will need to restart power-profile-daemon. >> >> I think that that is acceptable given that the user needs to manually >> poke things anyway. We should probably document this in the documentation >> for the sysfs attribute (as well as in newer versions of the p-p-d >> docs/README). >> >>> Some of those things we could change/fix, some other things will not. >>> If the platform_profile_choices file only contained a single item, >>> then power-profiles-daemon would just export the "low-power" and >>> "balanced" profiles to user-space, as it does on unsupported hardware. >> >> Right. >> >>> The profiles in power-profiles-daemon are supposed to show the user >>> intent, which having a single setting would effectively nullify. >> >> Yes that was my understanding too. >> >>> It's unclear to me how CnQF takes user intent into account (it's also >>> unclear to me how that's a low-power setting rather than a combination >>> of the existing cool and quiet settings). >> >> AMD folks, please correct me if any of the below is wrong: >> >> AFAIK even though it is called CnQF it is more like auto-profile >> selection and as such does not take user intent into account >> at all. > > Yes, You are right. Below is a brief note on how CnQF was designed. > > 1)CnQF – Cool And Quiet Framework - It’s an extension of the static > slider concept wherein PMF dynamically manages system power limits and > fan policy based on system power trends. > > 2)OEM can opt into the feature by defining the CnQF BIOS ACPI method. > > 3)Static slider control and CnQF are mutually exclusive. > > 4)CnQF supports up to 4 modes of operation – Turbo, Performance, > Balanced and Quiet. > > - It can be configured for AC and DC distinctly. > - PMF driver calculates the moving average of system power and switches > the mode of operation. > *If system power is limited to the threshold of the current mode, > move to the next higher mode > *If system power is not limited to the threshold of the current > mode, reduce the power budget by moving to the next lower mode. > > 5)CnQF feature control is through Radeon SW (a GUI based tool on Windows) > > To match the behavior on Windows, we kept a sysfs node to turn on/off > the CnQF on the fly like the way it can be done the windows side with > the Radeon SW tool. If you think that having as a module param makes > more sense, I am open to make the change and send a v2. > > Like I mentioned above, on Windows the static slider is absoultely dummy > when the user goes on turns on the CnQF from Radeon SW tool. Based on > the review remarks on the earlier series, we tried to > register/de-register to platform_profile, as per sysfs input (like > setting up and tearing down to platform_profile). > > The Difference between Auto-mode (for thinkpads) and CnQF(for others) is > that: > > - Automode gets turned on only when the slider position is set to > "balanced" in the platform_profile and > - a corresponding AMT ON event is triggered. > - it has 3 internal modes quiet, balanced, performance > > But for CnQF, > > - it is independent of the slider position and there are no ACPI events > for it to get kicked in. > - There are two seperate ACPI methods for AC and DC to get the > corresponding thermal values. > - it has 4 internal modes quiet, balanced, performance, turbo > > > There is already a WIP feature called "policy builder" where the OEMs > can build custom policies, which includes looking at the battery > percentages and making thermal optimizations accordingly. But this was > not taken into consideration while designing the CnQF on windows too. If > we bring in this change for Linux, there maybe differences in the way > the same feature behaves "differently" across OSes. > > Like you mentioned the usecase, where just a compilation can end up in > battery drain if not connected to AC power. Thanks for the explanation above. > Can we not have a > documentation update saying it is advised to turn "off" CnQF when > battery % goes below a certain level? So we would need to document that the user needs to poke the sysfs file when the battery is low ? That seems very user unfriendly. And also don't want power-performance-daemon to need to know about this AMD specific sysfs knob. That is why we have the standardized platform_profile userspace API. > That way, the end user experiences > across Linux and Windows remains the same. I can understand that you want to keep things the same. If I've read the above correctly then currently the user experience under Windows is that the slider in Windows has been turned into a dummy slider which does not do anything. That IMHO is quite a poor user-experience esp. when users want their battery to last longer because they are going to be e.g. on the road the entire day. >> It looks at the workload over a somewhat longer time period (say >> 5 minutes or so I guess?) and then if that consistently has been >> quite high, it will select something similar to performance. > > Right. The switch time would be dependent on the "time constant" values > set in the BIOS which is configurable to the OEMs. > >> >> Where as for a more mixed workload it will select balanced and for >> a mostly idle machine it will select low-power. >> >> I guess this auto feature is best treated the same as unsupported hw. >> >>> (it's also >>> unclear to me how that's a low-power setting rather than a combination >>> of the existing cool and quiet settings). >> >> Even though it is called cool and quiet AFAIK it won't be all that >> cool and quiet when running a heavy workload. Which is why I wonder >> how to re-conciliate this with showing low-power in e.g. the >> GNOME shell system men. Because in essence even if the battery >> is low the system will still go full-throttle when confronted >> with a heavy workload. >> >> So selecting low-power would result in the screen-dimming which >> I think is part of that, but the CPU's max power-consumption won't >> get limited as it would when platform-profiles are supported. >> >> So I guess this is indeed very much like how p-p-d behaves >> on unsupported hw... >> >> ### >> >> As mentioned I guess one option would be for CnQF to >> still register a platform_profile provider and then in >> balanced mode do its CnQF thing and in low-power mode >> disable CnQF and apply the static-slider low-power settings >> I think that that would work best from things actual >> working in a way I would expect the avarage end-user to >> expect things to work. >> >> So p-p-d would then still see platform-profile support >> in CnQF mode but with only low-power + balanced advertised. >> >> Bastien would that work for you? >> >> AMD folks would that also work for you ? > > If we go with the above proposal it would become very identical to what > is being done with automode (expect the extra "turbo" mode and not > having a AMT event). Yes I think that the AMT mode, where the more dynamic behavior os only done in balanced mode and low-power is still very much a low power-mode (and performance is always tuned for permance) makes a lot more sense from an enduser pov. Then the slider still actually works as expected and in the default balanced mode users will get the benefits of the new CnQF behavior / feature. > This would need some amount of discussion with our > windows folks also to know what they think about it. Ok. Regards, Hans
Hi, On 9/6/22 11:59, Shyam Sundar S K wrote: > Hi Bastien, Hans > > On 9/1/2022 7:04 PM, Bastien Nocera wrote: >> On Thu, 1 Sept 2022 at 14:44, Hans de Goede <hdegoede@redhat.com> wrote: >>> >>> Hi, >>> >>> On 9/1/22 14:24, Bastien Nocera wrote: >>>> On Thu, 1 Sept 2022 at 13:16, Hans de Goede <hdegoede@redhat.com> wrote: >>>>> >>>>> Hi, >>>>> >>>>> On 8/23/22 12:29, Shyam Sundar S K wrote: >>>>>> In this series, support for following features has been added. >>>>>> - "Cool n Quiet Framework (CnQF)" is an extension to the static slider, >>>>>> where the system power can be boosted or throttled independent >>>>>> of the selected slider position. >>>>>> - On the fly, the CnQF can be turned on/off via a sysfs knob. >>>>> >>>>> Thank you. I think that before doing a more in detail review >>>>> we first need to agree on the userspace interactions here. >>>>> >>>>> I've added Bastien, the power-profiles-daemon maintainer >>>>> to the Cc for this. >>>>> >>>>> From a quick peek at the patches I see that currently they do >>>>> the following: >>>>> >>>>> Probe time: >>>>> ----------- >>>>> >>>>> 1. If static slider (classic /sys/firmware/acpi/platform_profile) >>>>> is available register as a platform_profile provider >>>>> >>>>> 2. Query if the BIOS tells us that CnQF should be enable by >>>>> default if yes then unregister the platform_profile provider >>>>> and enable CnQF >>>>> >>>>> >>>>> Run time: >>>>> --------- >>>>> >>>>> Allow turning CnQF on/off by writing a sysfs attribute for this. >>>>> >>>>> 1. When CnQF gets enabled unregister the platform_profile provider >>>>> >>>>> 2. When CnQF gets disabled restore the last set profile and >>>>> register the platform_profile provider >>>>> >>>>> >>>>> Questions/remarks: >>>>> >>>>> 1. If you look at 1. and 2. under "Probe time", you will see that >>>>> when the BIOS requests to have CnQF enabled by default that >>>>> userspace will then still shortly see a platform_profile >>>>> provider. This must be fixed IMHO by checking whether to do >>>>> CnQF by default or not before the initial register call. >>>>> >>>>> 2. What about low-power scenarios ? Currently power-profiles-daemon >>>>> will always advertise a low-power mode even when there is no >>>>> platform-profile support, since this is also a hint for other >>>>> parts of the system to try and conserve power. But when this >>>>> mode is enabled we really want the system to also behave as >>>>> if the old static slider mode is active and set to low-power. >>>>> >>>>> Some ideas: >>>>> a) maybe still have the amd-pmf code register a (different) >>>>> platform_profile provider whn in CnQF mode and have it only >>>>> advertise low-power >>>>> >>>>> b) teach power-profiles-daemon about CnQF and have it >>>>> disable CnQF when entering low-power mode? >>>>> >>>>> c) make the CnQF code in PMF take the charge level into >>>>> account and have it not go "full throttle" when the chare >>>>> is below say 25% ? >>>>> >>>>> 3. Bastien, can power-profiles-daemon deal with >>>>> /sys/firmware/acpi/platform_profile disappearing or >>>>> appearing while it is running? >>>> >>>> No, it doesn't. >>>> >>>> It expects the platform_profile file to be available on startup, at >>>> worse with the choices not yet filled in. It doesn't handle the >>>> platform_profile file going away, it doesn't handle the >>>> platform_profile_choices file changing after it's been initially >>>> filled in, and it doesn't support less than one power profile being >>>> made available, and only supports hiding the performance profile if >>>> the platform doesn't support it. >>> >>> Ok, so this means that if we go with these changes as currently >>> proposed that if a user uses the sysfs file to turn CnQF on/off >>> they will need to restart power-profile-daemon. >>> >>> I think that that is acceptable given that the user needs to manually >>> poke things anyway. We should probably document this in the documentation >>> for the sysfs attribute (as well as in newer versions of the p-p-d >>> docs/README). >>> >>>> Some of those things we could change/fix, some other things will not. >>>> If the platform_profile_choices file only contained a single item, >>>> then power-profiles-daemon would just export the "low-power" and >>>> "balanced" profiles to user-space, as it does on unsupported hardware. >>> >>> Right. >>> >>>> The profiles in power-profiles-daemon are supposed to show the user >>>> intent, which having a single setting would effectively nullify. >>> >>> Yes that was my understanding too. >>> >>>> It's unclear to me how CnQF takes user intent into account (it's also >>>> unclear to me how that's a low-power setting rather than a combination >>>> of the existing cool and quiet settings). >>> >>> AMD folks, please correct me if any of the below is wrong: >>> >>> AFAIK even though it is called CnQF it is more like auto-profile >>> selection and as such does not take user intent into account >>> at all. >>> >>> It looks at the workload over a somewhat longer time period (say >>> 5 minutes or so I guess?) and then if that consistently has been >>> quite high, it will select something similar to performance. >>> >>> Where as for a more mixed workload it will select balanced and for >>> a mostly idle machine it will select low-power. >>> >>> I guess this auto feature is best treated the same as unsupported hw. >>> >>>> (it's also >>>> unclear to me how that's a low-power setting rather than a combination >>>> of the existing cool and quiet settings). >>> >>> Even though it is called cool and quiet AFAIK it won't be all that >>> cool and quiet when running a heavy workload. Which is why I wonder >>> how to re-conciliate this with showing low-power in e.g. the >>> GNOME shell system men. Because in essence even if the battery >>> is low the system will still go full-throttle when confronted >>> with a heavy workload. >>> >>> So selecting low-power would result in the screen-dimming which >>> I think is part of that, but the CPU's max power-consumption won't >>> get limited as it would when platform-profiles are supported. >>> >>> So I guess this is indeed very much like how p-p-d behaves >>> on unsupported hw... >>> >>> ### >>> >>> As mentioned I guess one option would be for CnQF to >>> still register a platform_profile provider and then in >>> balanced mode do its CnQF thing and in low-power mode >>> disable CnQF and apply the static-slider low-power settings >>> I think that that would work best from things actual >>> working in a way I would expect the avarage end-user to >>> expect things to work. >>> >>> So p-p-d would then still see platform-profile support >>> in CnQF mode but with only low-power + balanced advertised. >>> >>> Bastien would that work for you? >> >> That's something I can make work, yes. >> >>> AMD folks would that also work for you ? >>> >>> ### >>> >>> I'm also wondering if we are going to still export >>> balanced + low-power modes to userspace in CnQF mode >>> and disable CnQF in low-power mode then if we >>> even need a sysfs knob to turn it on/off at all. >>> >>> I guess the sysfs knob would then still be useful >>> to turn it on on systems where it defaults to off >>> in the BIOS. Might be better to do this as >>> a kernel-cmdline (module-param) then though, then we >>> also avoid the problem of platform_profile support >>> all of a sudden changing underneath's p-p-d's feet. >> >> I would say that, you could probably have CnQF transparently replacing >> the more static "balanced" profile if it is available, and have a >> separate setting to force enable/disable it as a kernel command-line >> for debugging or if the BIOS menu doesn't offer it as an option. >> >> That way the balanced mode would work like a more refined automatic >> profile switcher, and make the default experience better, without the >> disappearing profiles, or the user-space API headaches. >> > > module param would be fine to force load CnQF if the BIOS does not > advertise it. > > But I still think, having a sysfs node would still help to give an > option to the user to "opt-out" of the scenarios where he thinks that > battery can drain out if CnQF is turned on? Or in any case to turn > on/off CnQF on the fly, so that he can still switch back to the > traditional "static slider" based power optimizations. > > Please let me know your thoughts on this? Having a sysfs file to turn CnQF on/off seems best to me. Users who want to override the BIOS default at boot can then always do so with a little script or udev rule writing to the sysfs file. Regards, Hans
On Wed, 7 Sept 2022 at 16:35, Hans de Goede <hdegoede@redhat.com> wrote: > > Hi Bastien, > > On 9/7/22 16:24, Bastien Nocera wrote: > > Hey Shyam, > > > > I misunderstood that CnQF was a single setting, but it looks like it > > has 4 different levels, right? > > Unless there's a major malfunction, I don't think that offering to > > switch between 2 different policies where the difference is how > > "static" the performance boosts are is very useful, or comprehensible, > > to end-users. > > > > If CnQF only has a single "on" setting, then this could replace the > > balanced mode for what you call "static slider", so the end-user can > > still make a choice and have agency on whether the system tries to > > save power, or increase performance. > > > > If CnQF has multiple levels (Turbo, Performance, Balanced and Quiet, > > right?), then I don't think it's useful to have a sysfs setting to > > switch it at runtime, which only confuses user-space and the users. > > BIOS setting and/or kernel command-line option are the way to go. > > > > Did I understand this correctly? > > Let me try clarify things: > > CnQF has 4 levels internally, between which it switches automatically > based on the workload of the last 5 minutes. Oh, those profiles are internal only, OK. Do those automated levels behave like the "static slider" ones, to the point of being indistinguishable? So for example, does the static slider "performance" behave like "CnQF" if the machine was heavily loaded machine for 5 minutes?
Hi, On 9/7/22 17:35, Bastien Nocera wrote: > On Wed, 7 Sept 2022 at 16:35, Hans de Goede <hdegoede@redhat.com> wrote: >> >> Hi Bastien, >> >> On 9/7/22 16:24, Bastien Nocera wrote: >>> Hey Shyam, >>> >>> I misunderstood that CnQF was a single setting, but it looks like it >>> has 4 different levels, right? >>> Unless there's a major malfunction, I don't think that offering to >>> switch between 2 different policies where the difference is how >>> "static" the performance boosts are is very useful, or comprehensible, >>> to end-users. >>> >>> If CnQF only has a single "on" setting, then this could replace the >>> balanced mode for what you call "static slider", so the end-user can >>> still make a choice and have agency on whether the system tries to >>> save power, or increase performance. >>> >>> If CnQF has multiple levels (Turbo, Performance, Balanced and Quiet, >>> right?), then I don't think it's useful to have a sysfs setting to >>> switch it at runtime, which only confuses user-space and the users. >>> BIOS setting and/or kernel command-line option are the way to go. >>> >>> Did I understand this correctly? >> >> Let me try clarify things: >> >> CnQF has 4 levels internally, between which it switches automatically >> based on the workload of the last 5 minutes. > > Oh, those profiles are internal only, OK. Do those automated levels > behave like the "static slider" ones, to the point of being > indistinguishable? So for example, does the static slider > "performance" behave like "CnQF" if the machine was heavily loaded > machine for 5 minutes? This is more of a question for AMD to answer. But yes I believe that the CnQF internal performance mode which it boosts to if the machine is heavily loaded for 5 minutes is similar to the static slider performance setting. Regards, Hans
On 9/7/2022 8:18 PM, Hans de Goede wrote: > Hi, > > On 9/6/22 11:53, Shyam Sundar S K wrote: >> Hi Hans, >> >> Apologies for the delay in responding to this thread. Some responses below. > > No worries. > >> On 9/1/2022 6:14 PM, Hans de Goede wrote: >>> Hi, >>> >>> On 9/1/22 14:24, Bastien Nocera wrote: >>>> On Thu, 1 Sept 2022 at 13:16, Hans de Goede <hdegoede@redhat.com> wrote: >>>>> >>>>> Hi, >>>>> >>>>> On 8/23/22 12:29, Shyam Sundar S K wrote: >>>>>> In this series, support for following features has been added. >>>>>> - "Cool n Quiet Framework (CnQF)" is an extension to the static slider, >>>>>> where the system power can be boosted or throttled independent >>>>>> of the selected slider position. >>>>>> - On the fly, the CnQF can be turned on/off via a sysfs knob. >>>>> >>>>> Thank you. I think that before doing a more in detail review >>>>> we first need to agree on the userspace interactions here. >>>>> >>>>> I've added Bastien, the power-profiles-daemon maintainer >>>>> to the Cc for this. >>>>> >>>>> From a quick peek at the patches I see that currently they do >>>>> the following: >>>>> >>>>> Probe time: >>>>> ----------- >>>>> >>>>> 1. If static slider (classic /sys/firmware/acpi/platform_profile) >>>>> is available register as a platform_profile provider >>>>> >>>>> 2. Query if the BIOS tells us that CnQF should be enable by >>>>> default if yes then unregister the platform_profile provider >>>>> and enable CnQF >>>>> >>>>> >>>>> Run time: >>>>> --------- >>>>> >>>>> Allow turning CnQF on/off by writing a sysfs attribute for this. >>>>> >>>>> 1. When CnQF gets enabled unregister the platform_profile provider >>>>> >>>>> 2. When CnQF gets disabled restore the last set profile and >>>>> register the platform_profile provider >>>>> >>>>> >>>>> Questions/remarks: >>>>> >>>>> 1. If you look at 1. and 2. under "Probe time", you will see that >>>>> when the BIOS requests to have CnQF enabled by default that >>>>> userspace will then still shortly see a platform_profile >>>>> provider. This must be fixed IMHO by checking whether to do >>>>> CnQF by default or not before the initial register call. >>>>> >>>>> 2. What about low-power scenarios ? Currently power-profiles-daemon >>>>> will always advertise a low-power mode even when there is no >>>>> platform-profile support, since this is also a hint for other >>>>> parts of the system to try and conserve power. But when this >>>>> mode is enabled we really want the system to also behave as >>>>> if the old static slider mode is active and set to low-power. >>>>> >>>>> Some ideas: >>>>> a) maybe still have the amd-pmf code register a (different) >>>>> platform_profile provider whn in CnQF mode and have it only >>>>> advertise low-power >>>>> >>>>> b) teach power-profiles-daemon about CnQF and have it >>>>> disable CnQF when entering low-power mode? >>>>> >>>>> c) make the CnQF code in PMF take the charge level into >>>>> account and have it not go "full throttle" when the chare >>>>> is below say 25% ? >>>>> >>>>> 3. Bastien, can power-profiles-daemon deal with >>>>> /sys/firmware/acpi/platform_profile disappearing or >>>>> appearing while it is running? >>>> >>>> No, it doesn't. >>>> >>>> It expects the platform_profile file to be available on startup, at >>>> worse with the choices not yet filled in. It doesn't handle the >>>> platform_profile file going away, it doesn't handle the >>>> platform_profile_choices file changing after it's been initially >>>> filled in, and it doesn't support less than one power profile being >>>> made available, and only supports hiding the performance profile if >>>> the platform doesn't support it. >>> >>> Ok, so this means that if we go with these changes as currently >>> proposed that if a user uses the sysfs file to turn CnQF on/off >>> they will need to restart power-profile-daemon. >>> >>> I think that that is acceptable given that the user needs to manually >>> poke things anyway. We should probably document this in the documentation >>> for the sysfs attribute (as well as in newer versions of the p-p-d >>> docs/README). >>> >>>> Some of those things we could change/fix, some other things will not. >>>> If the platform_profile_choices file only contained a single item, >>>> then power-profiles-daemon would just export the "low-power" and >>>> "balanced" profiles to user-space, as it does on unsupported hardware. >>> >>> Right. >>> >>>> The profiles in power-profiles-daemon are supposed to show the user >>>> intent, which having a single setting would effectively nullify. >>> >>> Yes that was my understanding too. >>> >>>> It's unclear to me how CnQF takes user intent into account (it's also >>>> unclear to me how that's a low-power setting rather than a combination >>>> of the existing cool and quiet settings). >>> >>> AMD folks, please correct me if any of the below is wrong: >>> >>> AFAIK even though it is called CnQF it is more like auto-profile >>> selection and as such does not take user intent into account >>> at all. >> >> Yes, You are right. Below is a brief note on how CnQF was designed. >> >> 1)CnQF – Cool And Quiet Framework - It’s an extension of the static >> slider concept wherein PMF dynamically manages system power limits and >> fan policy based on system power trends. >> >> 2)OEM can opt into the feature by defining the CnQF BIOS ACPI method. >> >> 3)Static slider control and CnQF are mutually exclusive. >> >> 4)CnQF supports up to 4 modes of operation – Turbo, Performance, >> Balanced and Quiet. >> >> - It can be configured for AC and DC distinctly. >> - PMF driver calculates the moving average of system power and switches >> the mode of operation. >> *If system power is limited to the threshold of the current mode, >> move to the next higher mode >> *If system power is not limited to the threshold of the current >> mode, reduce the power budget by moving to the next lower mode. >> >> 5)CnQF feature control is through Radeon SW (a GUI based tool on Windows) >> >> To match the behavior on Windows, we kept a sysfs node to turn on/off >> the CnQF on the fly like the way it can be done the windows side with >> the Radeon SW tool. If you think that having as a module param makes >> more sense, I am open to make the change and send a v2. >> >> Like I mentioned above, on Windows the static slider is absoultely dummy >> when the user goes on turns on the CnQF from Radeon SW tool. Based on >> the review remarks on the earlier series, we tried to >> register/de-register to platform_profile, as per sysfs input (like >> setting up and tearing down to platform_profile). >> >> The Difference between Auto-mode (for thinkpads) and CnQF(for others) is >> that: >> >> - Automode gets turned on only when the slider position is set to >> "balanced" in the platform_profile and >> - a corresponding AMT ON event is triggered. >> - it has 3 internal modes quiet, balanced, performance >> >> But for CnQF, >> >> - it is independent of the slider position and there are no ACPI events >> for it to get kicked in. >> - There are two seperate ACPI methods for AC and DC to get the >> corresponding thermal values. >> - it has 4 internal modes quiet, balanced, performance, turbo >> >> >> There is already a WIP feature called "policy builder" where the OEMs >> can build custom policies, which includes looking at the battery >> percentages and making thermal optimizations accordingly. But this was >> not taken into consideration while designing the CnQF on windows too. If >> we bring in this change for Linux, there maybe differences in the way >> the same feature behaves "differently" across OSes. >> >> Like you mentioned the usecase, where just a compilation can end up in >> battery drain if not connected to AC power. > > Thanks for the explanation above. > >> Can we not have a >> documentation update saying it is advised to turn "off" CnQF when >> battery % goes below a certain level? > > So we would need to document that the user needs to poke > the sysfs file when the battery is low ? That seems very user > unfriendly. > > And also don't want power-performance-daemon to need to know about > this AMD specific sysfs knob. That is why we have the standardized > platform_profile userspace API. > >> That way, the end user experiences >> across Linux and Windows remains the same. > > I can understand that you want to keep things the same. If I've > read the above correctly then currently the user experience under > Windows is that the slider in Windows has been turned into a > dummy slider which does not do anything. > > That IMHO is quite a poor user-experience esp. when users want > their battery to last longer because they are going to be e.g. > on the road the entire day. > >>> It looks at the workload over a somewhat longer time period (say >>> 5 minutes or so I guess?) and then if that consistently has been >>> quite high, it will select something similar to performance. >> >> Right. The switch time would be dependent on the "time constant" values >> set in the BIOS which is configurable to the OEMs. >> >>> >>> Where as for a more mixed workload it will select balanced and for >>> a mostly idle machine it will select low-power. >>> >>> I guess this auto feature is best treated the same as unsupported hw. >>> >>>> (it's also >>>> unclear to me how that's a low-power setting rather than a combination >>>> of the existing cool and quiet settings). >>> >>> Even though it is called cool and quiet AFAIK it won't be all that >>> cool and quiet when running a heavy workload. Which is why I wonder >>> how to re-conciliate this with showing low-power in e.g. the >>> GNOME shell system men. Because in essence even if the battery >>> is low the system will still go full-throttle when confronted >>> with a heavy workload. >>> >>> So selecting low-power would result in the screen-dimming which >>> I think is part of that, but the CPU's max power-consumption won't >>> get limited as it would when platform-profiles are supported. >>> >>> So I guess this is indeed very much like how p-p-d behaves >>> on unsupported hw... >>> >>> ### >>> >>> As mentioned I guess one option would be for CnQF to >>> still register a platform_profile provider and then in >>> balanced mode do its CnQF thing and in low-power mode >>> disable CnQF and apply the static-slider low-power settings >>> I think that that would work best from things actual >>> working in a way I would expect the avarage end-user to >>> expect things to work. >>> >>> So p-p-d would then still see platform-profile support >>> in CnQF mode but with only low-power + balanced advertised. >>> >>> Bastien would that work for you? >>> >>> AMD folks would that also work for you ? >> >> If we go with the above proposal it would become very identical to what >> is being done with automode (expect the extra "turbo" mode and not >> having a AMT event). > > Yes I think that the AMT mode, where the more dynamic behavior os > only done in balanced mode and low-power is still very much a low > power-mode (and performance is always tuned for permance) makes > a lot more sense from an enduser pov. Then the slider still actually > works as expected and in the default balanced mode users will get > the benefits of the new CnQF behavior / feature. > >> This would need some amount of discussion with our >> windows folks also to know what they think about it. > > Ok. > OK. I get it. Your preference is to have CnQF getting ON only when 1. BIOS advertises CnQF is "supported" and/or 2. Sysfs knob is set to ON. and 3. the static-slider (platform_profile) is set to "balanced" In rest of the cases, (low-power or performance) the control would still remain with the static-slider so that, user can make his own choices. If that's the case, let me have a word with the windows team also on how we can have user experiences same across OSes and come back. Thank you for your feedback. Thanks, Shyam > Regards, > > Hans >
Hi, On 9/8/22 12:08, Shyam Sundar S K wrote: > > > On 9/7/2022 8:18 PM, Hans de Goede wrote: >> Hi, >> >> On 9/6/22 11:53, Shyam Sundar S K wrote: >>> Hi Hans, >>> >>> Apologies for the delay in responding to this thread. Some responses below. >> >> No worries. >> >>> On 9/1/2022 6:14 PM, Hans de Goede wrote: >>>> Hi, >>>> >>>> On 9/1/22 14:24, Bastien Nocera wrote: >>>>> On Thu, 1 Sept 2022 at 13:16, Hans de Goede <hdegoede@redhat.com> wrote: >>>>>> >>>>>> Hi, >>>>>> >>>>>> On 8/23/22 12:29, Shyam Sundar S K wrote: >>>>>>> In this series, support for following features has been added. >>>>>>> - "Cool n Quiet Framework (CnQF)" is an extension to the static slider, >>>>>>> where the system power can be boosted or throttled independent >>>>>>> of the selected slider position. >>>>>>> - On the fly, the CnQF can be turned on/off via a sysfs knob. >>>>>> >>>>>> Thank you. I think that before doing a more in detail review >>>>>> we first need to agree on the userspace interactions here. >>>>>> >>>>>> I've added Bastien, the power-profiles-daemon maintainer >>>>>> to the Cc for this. >>>>>> >>>>>> From a quick peek at the patches I see that currently they do >>>>>> the following: >>>>>> >>>>>> Probe time: >>>>>> ----------- >>>>>> >>>>>> 1. If static slider (classic /sys/firmware/acpi/platform_profile) >>>>>> is available register as a platform_profile provider >>>>>> >>>>>> 2. Query if the BIOS tells us that CnQF should be enable by >>>>>> default if yes then unregister the platform_profile provider >>>>>> and enable CnQF >>>>>> >>>>>> >>>>>> Run time: >>>>>> --------- >>>>>> >>>>>> Allow turning CnQF on/off by writing a sysfs attribute for this. >>>>>> >>>>>> 1. When CnQF gets enabled unregister the platform_profile provider >>>>>> >>>>>> 2. When CnQF gets disabled restore the last set profile and >>>>>> register the platform_profile provider >>>>>> >>>>>> >>>>>> Questions/remarks: >>>>>> >>>>>> 1. If you look at 1. and 2. under "Probe time", you will see that >>>>>> when the BIOS requests to have CnQF enabled by default that >>>>>> userspace will then still shortly see a platform_profile >>>>>> provider. This must be fixed IMHO by checking whether to do >>>>>> CnQF by default or not before the initial register call. >>>>>> >>>>>> 2. What about low-power scenarios ? Currently power-profiles-daemon >>>>>> will always advertise a low-power mode even when there is no >>>>>> platform-profile support, since this is also a hint for other >>>>>> parts of the system to try and conserve power. But when this >>>>>> mode is enabled we really want the system to also behave as >>>>>> if the old static slider mode is active and set to low-power. >>>>>> >>>>>> Some ideas: >>>>>> a) maybe still have the amd-pmf code register a (different) >>>>>> platform_profile provider whn in CnQF mode and have it only >>>>>> advertise low-power >>>>>> >>>>>> b) teach power-profiles-daemon about CnQF and have it >>>>>> disable CnQF when entering low-power mode? >>>>>> >>>>>> c) make the CnQF code in PMF take the charge level into >>>>>> account and have it not go "full throttle" when the chare >>>>>> is below say 25% ? >>>>>> >>>>>> 3. Bastien, can power-profiles-daemon deal with >>>>>> /sys/firmware/acpi/platform_profile disappearing or >>>>>> appearing while it is running? >>>>> >>>>> No, it doesn't. >>>>> >>>>> It expects the platform_profile file to be available on startup, at >>>>> worse with the choices not yet filled in. It doesn't handle the >>>>> platform_profile file going away, it doesn't handle the >>>>> platform_profile_choices file changing after it's been initially >>>>> filled in, and it doesn't support less than one power profile being >>>>> made available, and only supports hiding the performance profile if >>>>> the platform doesn't support it. >>>> >>>> Ok, so this means that if we go with these changes as currently >>>> proposed that if a user uses the sysfs file to turn CnQF on/off >>>> they will need to restart power-profile-daemon. >>>> >>>> I think that that is acceptable given that the user needs to manually >>>> poke things anyway. We should probably document this in the documentation >>>> for the sysfs attribute (as well as in newer versions of the p-p-d >>>> docs/README). >>>> >>>>> Some of those things we could change/fix, some other things will not. >>>>> If the platform_profile_choices file only contained a single item, >>>>> then power-profiles-daemon would just export the "low-power" and >>>>> "balanced" profiles to user-space, as it does on unsupported hardware. >>>> >>>> Right. >>>> >>>>> The profiles in power-profiles-daemon are supposed to show the user >>>>> intent, which having a single setting would effectively nullify. >>>> >>>> Yes that was my understanding too. >>>> >>>>> It's unclear to me how CnQF takes user intent into account (it's also >>>>> unclear to me how that's a low-power setting rather than a combination >>>>> of the existing cool and quiet settings). >>>> >>>> AMD folks, please correct me if any of the below is wrong: >>>> >>>> AFAIK even though it is called CnQF it is more like auto-profile >>>> selection and as such does not take user intent into account >>>> at all. >>> >>> Yes, You are right. Below is a brief note on how CnQF was designed. >>> >>> 1)CnQF – Cool And Quiet Framework - It’s an extension of the static >>> slider concept wherein PMF dynamically manages system power limits and >>> fan policy based on system power trends. >>> >>> 2)OEM can opt into the feature by defining the CnQF BIOS ACPI method. >>> >>> 3)Static slider control and CnQF are mutually exclusive. >>> >>> 4)CnQF supports up to 4 modes of operation – Turbo, Performance, >>> Balanced and Quiet. >>> >>> - It can be configured for AC and DC distinctly. >>> - PMF driver calculates the moving average of system power and switches >>> the mode of operation. >>> *If system power is limited to the threshold of the current mode, >>> move to the next higher mode >>> *If system power is not limited to the threshold of the current >>> mode, reduce the power budget by moving to the next lower mode. >>> >>> 5)CnQF feature control is through Radeon SW (a GUI based tool on Windows) >>> >>> To match the behavior on Windows, we kept a sysfs node to turn on/off >>> the CnQF on the fly like the way it can be done the windows side with >>> the Radeon SW tool. If you think that having as a module param makes >>> more sense, I am open to make the change and send a v2. >>> >>> Like I mentioned above, on Windows the static slider is absoultely dummy >>> when the user goes on turns on the CnQF from Radeon SW tool. Based on >>> the review remarks on the earlier series, we tried to >>> register/de-register to platform_profile, as per sysfs input (like >>> setting up and tearing down to platform_profile). >>> >>> The Difference between Auto-mode (for thinkpads) and CnQF(for others) is >>> that: >>> >>> - Automode gets turned on only when the slider position is set to >>> "balanced" in the platform_profile and >>> - a corresponding AMT ON event is triggered. >>> - it has 3 internal modes quiet, balanced, performance >>> >>> But for CnQF, >>> >>> - it is independent of the slider position and there are no ACPI events >>> for it to get kicked in. >>> - There are two seperate ACPI methods for AC and DC to get the >>> corresponding thermal values. >>> - it has 4 internal modes quiet, balanced, performance, turbo >>> >>> >>> There is already a WIP feature called "policy builder" where the OEMs >>> can build custom policies, which includes looking at the battery >>> percentages and making thermal optimizations accordingly. But this was >>> not taken into consideration while designing the CnQF on windows too. If >>> we bring in this change for Linux, there maybe differences in the way >>> the same feature behaves "differently" across OSes. >>> >>> Like you mentioned the usecase, where just a compilation can end up in >>> battery drain if not connected to AC power. >> >> Thanks for the explanation above. >> >>> Can we not have a >>> documentation update saying it is advised to turn "off" CnQF when >>> battery % goes below a certain level? >> >> So we would need to document that the user needs to poke >> the sysfs file when the battery is low ? That seems very user >> unfriendly. >> >> And also don't want power-performance-daemon to need to know about >> this AMD specific sysfs knob. That is why we have the standardized >> platform_profile userspace API. >> >>> That way, the end user experiences >>> across Linux and Windows remains the same. >> >> I can understand that you want to keep things the same. If I've >> read the above correctly then currently the user experience under >> Windows is that the slider in Windows has been turned into a >> dummy slider which does not do anything. >> >> That IMHO is quite a poor user-experience esp. when users want >> their battery to last longer because they are going to be e.g. >> on the road the entire day. >> >>>> It looks at the workload over a somewhat longer time period (say >>>> 5 minutes or so I guess?) and then if that consistently has been >>>> quite high, it will select something similar to performance. >>> >>> Right. The switch time would be dependent on the "time constant" values >>> set in the BIOS which is configurable to the OEMs. >>> >>>> >>>> Where as for a more mixed workload it will select balanced and for >>>> a mostly idle machine it will select low-power. >>>> >>>> I guess this auto feature is best treated the same as unsupported hw. >>>> >>>>> (it's also >>>>> unclear to me how that's a low-power setting rather than a combination >>>>> of the existing cool and quiet settings). >>>> >>>> Even though it is called cool and quiet AFAIK it won't be all that >>>> cool and quiet when running a heavy workload. Which is why I wonder >>>> how to re-conciliate this with showing low-power in e.g. the >>>> GNOME shell system men. Because in essence even if the battery >>>> is low the system will still go full-throttle when confronted >>>> with a heavy workload. >>>> >>>> So selecting low-power would result in the screen-dimming which >>>> I think is part of that, but the CPU's max power-consumption won't >>>> get limited as it would when platform-profiles are supported. >>>> >>>> So I guess this is indeed very much like how p-p-d behaves >>>> on unsupported hw... >>>> >>>> ### >>>> >>>> As mentioned I guess one option would be for CnQF to >>>> still register a platform_profile provider and then in >>>> balanced mode do its CnQF thing and in low-power mode >>>> disable CnQF and apply the static-slider low-power settings >>>> I think that that would work best from things actual >>>> working in a way I would expect the avarage end-user to >>>> expect things to work. >>>> >>>> So p-p-d would then still see platform-profile support >>>> in CnQF mode but with only low-power + balanced advertised. >>>> >>>> Bastien would that work for you? >>>> >>>> AMD folks would that also work for you ? >>> >>> If we go with the above proposal it would become very identical to what >>> is being done with automode (expect the extra "turbo" mode and not >>> having a AMT event). >> >> Yes I think that the AMT mode, where the more dynamic behavior os >> only done in balanced mode and low-power is still very much a low >> power-mode (and performance is always tuned for permance) makes >> a lot more sense from an enduser pov. Then the slider still actually >> works as expected and in the default balanced mode users will get >> the benefits of the new CnQF behavior / feature. >> >>> This would need some amount of discussion with our >>> windows folks also to know what they think about it. >> >> Ok. >> > > OK. I get it. Your preference is to have CnQF getting ON only when > > 1. BIOS advertises CnQF is "supported" and/or > 2. Sysfs knob is set to ON. and > 3. the static-slider (platform_profile) is set to "balanced" > > In rest of the cases, (low-power or performance) the control would still > remain with the static-slider so that, user can make his own choices. Yes that is correct. > If that's the case, let me have a word with the windows team also on how > we can have user experiences same across OSes and come back. Great, thank you. Regards, Hans
Hi Bastien, On 9/8/2022 2:38 PM, Hans de Goede wrote: > Hi, > > On 9/7/22 17:35, Bastien Nocera wrote: >> On Wed, 7 Sept 2022 at 16:35, Hans de Goede <hdegoede@redhat.com> wrote: >>> >>> Hi Bastien, >>> >>> On 9/7/22 16:24, Bastien Nocera wrote: >>>> Hey Shyam, >>>> >>>> I misunderstood that CnQF was a single setting, but it looks like it >>>> has 4 different levels, right? >>>> Unless there's a major malfunction, I don't think that offering to >>>> switch between 2 different policies where the difference is how >>>> "static" the performance boosts are is very useful, or comprehensible, >>>> to end-users. >>>> >>>> If CnQF only has a single "on" setting, then this could replace the >>>> balanced mode for what you call "static slider", so the end-user can >>>> still make a choice and have agency on whether the system tries to >>>> save power, or increase performance. >>>> >>>> If CnQF has multiple levels (Turbo, Performance, Balanced and Quiet, >>>> right?), then I don't think it's useful to have a sysfs setting to >>>> switch it at runtime, which only confuses user-space and the users. >>>> BIOS setting and/or kernel command-line option are the way to go. >>>> >>>> Did I understand this correctly? >>> >>> Let me try clarify things: >>> >>> CnQF has 4 levels internally, between which it switches automatically >>> based on the workload of the last 5 minutes. >> >> Oh, those profiles are internal only, OK. Do those automated levels >> behave like the "static slider" ones, to the point of being >> indistinguishable? So for example, does the static slider >> "performance" behave like "CnQF" if the machine was heavily loaded >> machine for 5 minutes? > > This is more of a question for AMD to answer. But yes I believe that > the CnQF internal performance mode which it boosts to if the machine > is heavily loaded for 5 minutes is similar to the static slider > performance setting. Its a kind of "yes". But its still dependent on how the OEMs have tuned the power profiling values and mapped it to the relavant CnQF modes. Thanks, Shyam > > Regards, > > Hans >
In this series, support for following features has been added. - "Cool n Quiet Framework (CnQF)" is an extension to the static slider, where the system power can be boosted or throttled independent of the selected slider position. - On the fly, the CnQF can be turned on/off via a sysfs knob. Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com> Shyam Sundar S K (4): platform/x86/amd/pmf: Add support for CnQF platform/x86/amd/pmf: Add sysfs to toggle CnQF Documentation/ABI/testing/sysfs-amd-pmf: Add ABI doc for AMD PMF MAINTAINERS: Update ABI doc path for AMD PMF Documentation/ABI/testing/sysfs-amd-pmf | 11 + MAINTAINERS | 1 + drivers/platform/x86/amd/pmf/Makefile | 2 +- drivers/platform/x86/amd/pmf/acpi.c | 10 + drivers/platform/x86/amd/pmf/cnqf.c | 374 ++++++++++++++++++++++++ drivers/platform/x86/amd/pmf/core.c | 16 +- drivers/platform/x86/amd/pmf/pmf.h | 100 +++++++ 7 files changed, 512 insertions(+), 2 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-amd-pmf create mode 100644 drivers/platform/x86/amd/pmf/cnqf.c