| Message ID | 1462251879-7224-1-git-send-email-edubezval@gmail.com (mailing list archive) |
|---|---|
| State | Rejected, archived |
| Delegated to: | Rafael Wysocki |
| Headers | show |
On Tue, May 3, 2016 at 7:04 AM, Eduardo Valentin <edubezval@gmail.com> wrote: > Currently, in an ACPI based system, the processor driver registers > one cooling device per processor. However, the cooling device type > is the same for each processor. For example, on a system with four > processors, the sysfs reading of each cooling device would look like: > ebv@besouro ~ $ cat /sys/class/thermal/cooling_device*/type > Processor > Processor > Processor > Processor > > which turns out to fine. But, some parts of the thermal code may use > type to identify participating devices in a thermal zone. Besides, > adding notifications to user space may cause the production of messages > that may confuse the listener. > > For this reason, this patch adds the processor ID cooling device type. > After this change, the cooling device listing in the same previous example > would look like this: > ebv@besouro ~ $ cat /sys/class/thermal/cooling_device*/type > Processor.0 > Processor.1 > Processor.2 > Processor.3 > > allowing an easier identification of cooling device target. Is it not going to confuse any user space scripts or similar? -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, 2016-05-04 at 23:49 +0200, Rafael J. Wysocki wrote: > On Tue, May 3, 2016 at 7:04 AM, Eduardo Valentin <edubezval@gmail.com > > wrote: > > > > Currently, in an ACPI based system, the processor driver registers > > one cooling device per processor. However, the cooling device type > > is the same for each processor. For example, on a system with four > > processors, the sysfs reading of each cooling device would look > > like: > > ebv@besouro ~ $ cat /sys/class/thermal/cooling_device*/type > > Processor > > Processor > > Processor > > Processor > > > > which turns out to fine. But, some parts of the thermal code may > > use > > type to identify participating devices in a thermal zone. Besides, > > adding notifications to user space may cause the production of > > messages > > that may confuse the listener. > > > > For this reason, this patch adds the processor ID cooling device > > type. > > After this change, the cooling device listing in the same previous > > example > > would look like this: > > ebv@besouro ~ $ cat /sys/class/thermal/cooling_device*/type > > Processor.0 > > Processor.1 > > Processor.2 > > Processor.3 > > > > allowing an easier identification of cooling device target. > Is it not going to confuse any user space scripts or similar? Yes, it will. Thanks, Srinivas -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wednesday, May 04, 2016 02:54:32 PM Srinivas Pandruvada wrote: > On Wed, 2016-05-04 at 23:49 +0200, Rafael J. Wysocki wrote: > > On Tue, May 3, 2016 at 7:04 AM, Eduardo Valentin <edubezval@gmail.com > > > wrote: > > > > > > Currently, in an ACPI based system, the processor driver registers > > > one cooling device per processor. However, the cooling device type > > > is the same for each processor. For example, on a system with four > > > processors, the sysfs reading of each cooling device would look > > > like: > > > ebv@besouro ~ $ cat /sys/class/thermal/cooling_device*/type > > > Processor > > > Processor > > > Processor > > > Processor > > > > > > which turns out to fine. But, some parts of the thermal code may > > > use > > > type to identify participating devices in a thermal zone. Besides, > > > adding notifications to user space may cause the production of > > > messages > > > that may confuse the listener. > > > > > > For this reason, this patch adds the processor ID cooling device > > > type. > > > After this change, the cooling device listing in the same previous > > > example > > > would look like this: > > > ebv@besouro ~ $ cat /sys/class/thermal/cooling_device*/type > > > Processor.0 > > > Processor.1 > > > Processor.2 > > > Processor.3 > > > > > > allowing an easier identification of cooling device target. > > > > Is it not going to confuse any user space scripts or similar? > > Yes, it will. In that case the patch cannot be applied. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, May 05, 2016 at 12:00:57AM +0200, Rafael J. Wysocki wrote: > On Wednesday, May 04, 2016 02:54:32 PM Srinivas Pandruvada wrote: > > On Wed, 2016-05-04 at 23:49 +0200, Rafael J. Wysocki wrote: > > > On Tue, May 3, 2016 at 7:04 AM, Eduardo Valentin <edubezval@gmail.com > > > > wrote: > > > > > > > > Currently, in an ACPI based system, the processor driver registers > > > > one cooling device per processor. However, the cooling device type > > > > is the same for each processor. For example, on a system with four > > > > processors, the sysfs reading of each cooling device would look > > > > like: > > > > ebv@besouro ~ $ cat /sys/class/thermal/cooling_device*/type > > > > Processor > > > > Processor > > > > Processor > > > > Processor > > > > > > > > which turns out to fine. But, some parts of the thermal code may > > > > use > > > > type to identify participating devices in a thermal zone. Besides, > > > > adding notifications to user space may cause the production of > > > > messages > > > > that may confuse the listener. > > > > > > > > For this reason, this patch adds the processor ID cooling device > > > > type. > > > > After this change, the cooling device listing in the same previous > > > > example > > > > would look like this: > > > > ebv@besouro ~ $ cat /sys/class/thermal/cooling_device*/type > > > > Processor.0 > > > > Processor.1 > > > > Processor.2 > > > > Processor.3 > > > > > > > > allowing an easier identification of cooling device target. > > > > > > Is it not going to confuse any user space scripts or similar? > > > > Yes, it will. > > In that case the patch cannot be applied. In fact, we shall never brake userspace. Srinivas, could you please elaborate a bit more on how this would break userspace? How different would it be having an extra id? Are you expecting "Processor" string in daemon? BR, > > Thanks, > Rafael > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Eduardo, On Wed, 2016-05-04 at 20:06 -0700, Eduardo Valentin wrote: > On Thu, May 05, 2016 at 12:00:57AM +0200, Rafael J. Wysocki wrote: > > > > On Wednesday, May 04, 2016 02:54:32 PM Srinivas Pandruvada wrote: > > > > > > On Wed, 2016-05-04 at 23:49 +0200, Rafael J. Wysocki wrote: > > > > > > > > On Tue, May 3, 2016 at 7:04 AM, Eduardo Valentin <edubezval@gma > > > > il.com > > > > > > > > > > wrote: > > > > > > > > > > Currently, in an ACPI based system, the processor driver > > > > > registers > > > > > one cooling device per processor. However, the cooling device > > > > > type > > > > > is the same for each processor. For example, on a system with > > > > > four > > > > > processors, the sysfs reading of each cooling device would > > > > > look > > > > > like: > > > > > ebv@besouro ~ $ cat /sys/class/thermal/cooling_device*/type > > > > > Processor > > > > > Processor > > > > > Processor > > > > > Processor > > > > > > > > > > which turns out to fine. But, some parts of the thermal code > > > > > may > > > > > use > > > > > type to identify participating devices in a thermal zone. > > > > > Besides, > > > > > adding notifications to user space may cause the production > > > > > of > > > > > messages > > > > > that may confuse the listener. > > > > > > > > > > For this reason, this patch adds the processor ID cooling > > > > > device > > > > > type. > > > > > After this change, the cooling device listing in the same > > > > > previous > > > > > example > > > > > would look like this: > > > > > ebv@besouro ~ $ cat /sys/class/thermal/cooling_device*/type > > > > > Processor.0 > > > > > Processor.1 > > > > > Processor.2 > > > > > Processor.3 > > > > > > > > > > allowing an easier identification of cooling device target. > > > > Is it not going to confuse any user space scripts or similar? > > > Yes, it will. > > In that case the patch cannot be applied. > In fact, we shall never brake userspace. > > Srinivas, could you please elaborate a bit more on how this would > break > userspace? How different would it be having an extra id? Are you > expecting "Processor" string in daemon? Yes. Also Processor is a special type of cdev on client systems. So you set a state in one Processor all Processors cooling device gets changed as they share voltage and frequency. So they all are same. So if some user space tries to reduce the cur_state by 1 for all the processor cooling devices they will effectively reduce cur_state to much lower value. So instead of this, we should have only one processor cooling device per CPU package, so on most of the client systems, we will see only one processor cooling device. Thanks, Srinivas > > BR, > > > > > > > Thanks, > > Rafael > > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c index d2fa8cb..6e982c1 100644 --- a/drivers/acpi/processor_driver.c +++ b/drivers/acpi/processor_driver.c @@ -163,6 +163,7 @@ static struct notifier_block acpi_cpu_notifier = { static int acpi_pss_perf_init(struct acpi_processor *pr, struct acpi_device *device) { + char cdev_name[THERMAL_NAME_LENGTH]; int result = 0; acpi_processor_ppc_has_changed(pr, 0); @@ -172,7 +173,8 @@ static int acpi_pss_perf_init(struct acpi_processor *pr, if (pr->flags.throttling) pr->flags.limit = 1; - pr->cdev = thermal_cooling_device_register("Processor", device, + snprintf(cdev_name, sizeof(cdev_name), "Processor.%d", pr->id); + pr->cdev = thermal_cooling_device_register(cdev_name, device, &processor_cooling_ops); if (IS_ERR(pr->cdev)) { result = PTR_ERR(pr->cdev);
Currently, in an ACPI based system, the processor driver registers one cooling device per processor. However, the cooling device type is the same for each processor. For example, on a system with four processors, the sysfs reading of each cooling device would look like: ebv@besouro ~ $ cat /sys/class/thermal/cooling_device*/type Processor Processor Processor Processor which turns out to fine. But, some parts of the thermal code may use type to identify participating devices in a thermal zone. Besides, adding notifications to user space may cause the production of messages that may confuse the listener. For this reason, this patch adds the processor ID cooling device type. After this change, the cooling device listing in the same previous example would look like this: ebv@besouro ~ $ cat /sys/class/thermal/cooling_device*/type Processor.0 Processor.1 Processor.2 Processor.3 allowing an easier identification of cooling device target. Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Len Brown <lenb@kernel.org> Cc: linux-acpi@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Eduardo Valentin <edubezval@gmail.com> --- drivers/acpi/processor_driver.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)