| Message ID | 20170501223913.6894-1-xypron.glpk@gmx.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, May 02, 2017 at 12:39:13AM +0200, Heinrich Schuchardt wrote: > There is no need to hide the model name in processes > that are not PER_LINUX32. > > So let us always provide a model name that is easily readable. > > Fixes: e47b020a323d ("arm64: Provide "model name" in /proc/cpuinfo for PER_LINUX32 tasks") > Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> > --- > arch/arm64/kernel/cpuinfo.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c > index b3d5b3e8fbcb..9ad9ddcd2f19 100644 > --- a/arch/arm64/kernel/cpuinfo.c > +++ b/arch/arm64/kernel/cpuinfo.c > @@ -118,9 +118,8 @@ static int c_show(struct seq_file *m, void *v) > * "processor". Give glibc what it expects. > */ > seq_printf(m, "processor\t: %d\n", i); > - if (compat) > - seq_printf(m, "model name\t: ARMv8 Processor rev %d (%s)\n", > - MIDR_REVISION(midr), COMPAT_ELF_PLATFORM); > + seq_printf(m, "model name\t: ARMv8 Processor rev %d (%s)\n", > + MIDR_REVISION(midr), COMPAT_ELF_PLATFORM); > > seq_printf(m, "BogoMIPS\t: %lu.%02lu\n", > loops_per_jiffy / (500000UL/HZ), Such patch seems to come up regularly: https://patchwork.kernel.org/patch/9303311/ (and it usually gets rejected)
On Tue, May 02, 2017 at 12:08:27PM +0100, Catalin Marinas wrote: > On Tue, May 02, 2017 at 12:39:13AM +0200, Heinrich Schuchardt wrote: > > There is no need to hide the model name in processes > > that are not PER_LINUX32. > > > > So let us always provide a model name that is easily readable. > > > > Fixes: e47b020a323d ("arm64: Provide "model name" in /proc/cpuinfo for PER_LINUX32 tasks") > > Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> > > --- > > arch/arm64/kernel/cpuinfo.c | 5 ++--- > > 1 file changed, 2 insertions(+), 3 deletions(-) > > > > diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c > > index b3d5b3e8fbcb..9ad9ddcd2f19 100644 > > --- a/arch/arm64/kernel/cpuinfo.c > > +++ b/arch/arm64/kernel/cpuinfo.c > > @@ -118,9 +118,8 @@ static int c_show(struct seq_file *m, void *v) > > * "processor". Give glibc what it expects. > > */ > > seq_printf(m, "processor\t: %d\n", i); > > - if (compat) > > - seq_printf(m, "model name\t: ARMv8 Processor rev %d (%s)\n", > > - MIDR_REVISION(midr), COMPAT_ELF_PLATFORM); > > + seq_printf(m, "model name\t: ARMv8 Processor rev %d (%s)\n", > > + MIDR_REVISION(midr), COMPAT_ELF_PLATFORM); > > > > seq_printf(m, "BogoMIPS\t: %lu.%02lu\n", > > loops_per_jiffy / (500000UL/HZ), > > Such patch seems to come up regularly: > > https://patchwork.kernel.org/patch/9303311/ > > (and it usually gets rejected) Indeed; my comments from that previous discussion apply here. In addition, the commit message above refers to this as fixing another commit, but does not explain why the current behviour would be considered a bug. I do not think it makes sense to take this patch. Thanks, Mark.
On 05/02/2017 01:08 PM, Catalin Marinas wrote: > On Tue, May 02, 2017 at 12:39:13AM +0200, Heinrich Schuchardt wrote: >> There is no need to hide the model name in processes >> that are not PER_LINUX32. >> >> So let us always provide a model name that is easily readable. >> >> Fixes: e47b020a323d ("arm64: Provide "model name" in /proc/cpuinfo for PER_LINUX32 tasks") >> Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> >> --- >> arch/arm64/kernel/cpuinfo.c | 5 ++--- >> 1 file changed, 2 insertions(+), 3 deletions(-) >> >> diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c >> index b3d5b3e8fbcb..9ad9ddcd2f19 100644 >> --- a/arch/arm64/kernel/cpuinfo.c >> +++ b/arch/arm64/kernel/cpuinfo.c >> @@ -118,9 +118,8 @@ static int c_show(struct seq_file *m, void *v) >> * "processor". Give glibc what it expects. >> */ >> seq_printf(m, "processor\t: %d\n", i); >> - if (compat) >> - seq_printf(m, "model name\t: ARMv8 Processor rev %d (%s)\n", >> - MIDR_REVISION(midr), COMPAT_ELF_PLATFORM); >> + seq_printf(m, "model name\t: ARMv8 Processor rev %d (%s)\n", >> + MIDR_REVISION(midr), COMPAT_ELF_PLATFORM); >> >> seq_printf(m, "BogoMIPS\t: %lu.%02lu\n", >> loops_per_jiffy / (500000UL/HZ), > > Such patch seems to come up regularly: > > https://patchwork.kernel.org/patch/9303311/ > > (and it usually gets rejected) > Dear Catalin, thank you for pointing me to the previous discussion. I understand that adding model name in the current form would not provide sufficient valuable information. The real interesting thing in an ARM SOC is to see which CPU is A72, A57, A53 or whatever. This information is available from the device tree in the compatible property of the individual CPUs (/sys/firmware/devicetree/base/cpus/cpu@*/compatible), e.g. compatible =3D "arm,cortex-a53", "arm,armv8"; I guess this information is the closest to the model name property on other architectures that we can get. Would exposing this information in /proc/cpuinfo as 'model name' make sense to you? Best regards Heinrich
On 02/05/17 17:28, Heinrich Schuchardt wrote: [...] > The real interesting thing in an ARM SOC is to see which CPU is A72, > A57, A53 or whatever. > > This information is available from the device tree in the compatible > property of the individual CPUs > (/sys/firmware/devicetree/base/cpus/cpu@*/compatible), e.g. > compatible =3D "arm,cortex-a53", "arm,armv8"; > You can refer "CPU part" in /proc/cpuinfo for the above information.
On Tue, May 02, 2017 at 06:28:40PM +0200, Heinrich Schuchardt wrote: > On 05/02/2017 01:08 PM, Catalin Marinas wrote: > > On Tue, May 02, 2017 at 12:39:13AM +0200, Heinrich Schuchardt wrote: > >> There is no need to hide the model name in processes > >> that are not PER_LINUX32. > >> > >> So let us always provide a model name that is easily readable. > >> > >> Fixes: e47b020a323d ("arm64: Provide "model name" in /proc/cpuinfo for PER_LINUX32 tasks") > >> Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> > >> --- > >> arch/arm64/kernel/cpuinfo.c | 5 ++--- > >> 1 file changed, 2 insertions(+), 3 deletions(-) > >> > >> diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c > >> index b3d5b3e8fbcb..9ad9ddcd2f19 100644 > >> --- a/arch/arm64/kernel/cpuinfo.c > >> +++ b/arch/arm64/kernel/cpuinfo.c > >> @@ -118,9 +118,8 @@ static int c_show(struct seq_file *m, void *v) > >> * "processor". Give glibc what it expects. > >> */ > >> seq_printf(m, "processor\t: %d\n", i); > >> - if (compat) > >> - seq_printf(m, "model name\t: ARMv8 Processor rev %d (%s)\n", > >> - MIDR_REVISION(midr), COMPAT_ELF_PLATFORM); > >> + seq_printf(m, "model name\t: ARMv8 Processor rev %d (%s)\n", > >> + MIDR_REVISION(midr), COMPAT_ELF_PLATFORM); > >> > >> seq_printf(m, "BogoMIPS\t: %lu.%02lu\n", > >> loops_per_jiffy / (500000UL/HZ), > > > > Such patch seems to come up regularly: > > > > https://patchwork.kernel.org/patch/9303311/ > > > > (and it usually gets rejected) > > > Dear Catalin, > > thank you for pointing me to the previous discussion. I understand that > adding model name in the current form would not provide sufficient > valuable information. > > The real interesting thing in an ARM SOC is to see which CPU is A72, > A57, A53 or whatever. This information can be derived from the MIDR fields exposed in /proc/cpuninfo e.g. CPU implementer : 0x41 CPU architecture: 8 CPU variant : 0x1 CPU part : 0xd07 CPU revision : 2 ... is a Cortex-A57. > This information is available from the device tree in the compatible > property of the individual CPUs > (/sys/firmware/devicetree/base/cpus/cpu@*/compatible), e.g. > compatible =3D "arm,cortex-a53", "arm,armv8"; > > I guess this information is the closest to the model name property on > other architectures that we can get. > > Would exposing this information in /proc/cpuinfo as 'model name' make > sense to you? I would disagree with exposing this, as in practice it is wrong in some DTs, and it's not avaialble on ACPI systems. We already expose the information necessary to derive the name, given a lookup table in userspace. We don't have sufficient information to build this in the kernel in all cases, so I don't think that we should attempt to do so. Thanks, Mark.
On 05/02/2017 07:08 AM, Catalin Marinas wrote: > On Tue, May 02, 2017 at 12:39:13AM +0200, Heinrich Schuchardt wrote: >> There is no need to hide the model name in processes >> that are not PER_LINUX32. >> >> So let us always provide a model name that is easily readable. >> >> Fixes: e47b020a323d ("arm64: Provide "model name" in /proc/cpuinfo for PER_LINUX32 tasks") >> Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> >> --- >> arch/arm64/kernel/cpuinfo.c | 5 ++--- >> 1 file changed, 2 insertions(+), 3 deletions(-) >> >> diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c >> index b3d5b3e8fbcb..9ad9ddcd2f19 100644 >> --- a/arch/arm64/kernel/cpuinfo.c >> +++ b/arch/arm64/kernel/cpuinfo.c >> @@ -118,9 +118,8 @@ static int c_show(struct seq_file *m, void *v) >> * "processor". Give glibc what it expects. >> */ >> seq_printf(m, "processor\t: %d\n", i); >> - if (compat) >> - seq_printf(m, "model name\t: ARMv8 Processor rev %d (%s)\n", >> - MIDR_REVISION(midr), COMPAT_ELF_PLATFORM); >> + seq_printf(m, "model name\t: ARMv8 Processor rev %d (%s)\n", >> + MIDR_REVISION(midr), COMPAT_ELF_PLATFORM); >> >> seq_printf(m, "BogoMIPS\t: %lu.%02lu\n", >> loops_per_jiffy / (500000UL/HZ), > > Such patch seems to come up regularly: > > https://patchwork.kernel.org/patch/9303311/ > > (and it usually gets rejected) Side note: I'm in the process of reviving a standardization discussion around server and model information, and we'll be coming back with an agenda to get this information in /proc/cpuinfo in coming months. Jon.
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c index b3d5b3e8fbcb..9ad9ddcd2f19 100644 --- a/arch/arm64/kernel/cpuinfo.c +++ b/arch/arm64/kernel/cpuinfo.c @@ -118,9 +118,8 @@ static int c_show(struct seq_file *m, void *v) * "processor". Give glibc what it expects. */ seq_printf(m, "processor\t: %d\n", i); - if (compat) - seq_printf(m, "model name\t: ARMv8 Processor rev %d (%s)\n", - MIDR_REVISION(midr), COMPAT_ELF_PLATFORM); + seq_printf(m, "model name\t: ARMv8 Processor rev %d (%s)\n", + MIDR_REVISION(midr), COMPAT_ELF_PLATFORM); seq_printf(m, "BogoMIPS\t: %lu.%02lu\n", loops_per_jiffy / (500000UL/HZ),
There is no need to hide the model name in processes that are not PER_LINUX32. So let us always provide a model name that is easily readable. Fixes: e47b020a323d ("arm64: Provide "model name" in /proc/cpuinfo for PER_LINUX32 tasks") Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> --- arch/arm64/kernel/cpuinfo.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)