* [PATCH] tools/power/turbostat: fix compatibility with older kernels
@ 2021-01-27 13:24 Artem Bityutskiy
2021-01-27 18:59 ` Borislav Petkov
2021-02-03 11:06 ` [tip: x86/urgent] tools/power/turbostat: Fallback to an MSR read for EPB tip-bot2 for Borislav Petkov
0 siblings, 2 replies; 6+ messages in thread
From: Artem Bityutskiy @ 2021-01-27 13:24 UTC (permalink / raw)
To: Rafael J. Wysocki, Len Brown
Cc: Linux PM Mailing List, Borislav Petkov, Artem Bityutskiy
From: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Commit
6d6501d912a9 tools/power/turbostat: Read energy_perf_bias from sysfs
added a useful EPB print by reading EPB from sysfs's 'energy_perf_bias' file.
However, older kernels, which do not necessarily have that sysfs file (e.g.,
Centos 7's stock kernel does not have it). As a result, turbostat fails with
older kernels.
This patch fixes the problem by ignoring the sysfs file read errors.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
---
tools/power/x86/turbostat/turbostat.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 389ea5209a83..12e014f2c24b 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -1839,7 +1839,9 @@ int get_epb(int cpu)
sprintf(path, "/sys/devices/system/cpu/cpu%d/power/energy_perf_bias", cpu);
- fp = fopen_or_die(path, "r");
+ fp = fopen(path, "r");
+ if (!fp)
+ return -1;
ret = fscanf(fp, "%d", &epb);
if (ret != 1)
--
2.26.2
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] tools/power/turbostat: fix compatibility with older kernels
2021-01-27 13:24 [PATCH] tools/power/turbostat: fix compatibility with older kernels Artem Bityutskiy
@ 2021-01-27 18:59 ` Borislav Petkov
2021-01-27 20:15 ` Doug Smythies
2021-02-03 11:06 ` [tip: x86/urgent] tools/power/turbostat: Fallback to an MSR read for EPB tip-bot2 for Borislav Petkov
1 sibling, 1 reply; 6+ messages in thread
From: Borislav Petkov @ 2021-01-27 18:59 UTC (permalink / raw)
To: Artem Bityutskiy; +Cc: Rafael J. Wysocki, Len Brown, Linux PM Mailing List
On Wed, Jan 27, 2021 at 03:24:44PM +0200, Artem Bityutskiy wrote:
> From: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
>
> Commit
>
> 6d6501d912a9 tools/power/turbostat: Read energy_perf_bias from sysfs
>
> added a useful EPB print by reading EPB from sysfs's 'energy_perf_bias' file.
> However, older kernels, which do not necessarily have that sysfs file (e.g.,
> Centos 7's stock kernel does not have it). As a result, turbostat fails with
> older kernels.
>
> This patch fixes the problem by ignoring the sysfs file read errors.
>
> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
> ---
> tools/power/x86/turbostat/turbostat.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
> index 389ea5209a83..12e014f2c24b 100644
> --- a/tools/power/x86/turbostat/turbostat.c
> +++ b/tools/power/x86/turbostat/turbostat.c
> @@ -1839,7 +1839,9 @@ int get_epb(int cpu)
>
> sprintf(path, "/sys/devices/system/cpu/cpu%d/power/energy_perf_bias", cpu);
>
> - fp = fopen_or_die(path, "r");
> + fp = fopen(path, "r");
> + if (!fp)
> + return -1;
>
> ret = fscanf(fp, "%d", &epb);
> if (ret != 1)
So I was under the impression that things in tools/ are tied to the
kernel version they're shipped with. Which means, you should probably
get the one from the centos kernel.
However, if this is supposed to work on older kernels too, then
6d6501d912a9 ("tools/power/turbostat: Read energy_perf_bias from sysfs")
would need to be extended to first test the sysfs file's existence and
if not there, fall back to the MSR reading...
--
Regards/Gruss,
Boris.
SUSE Software Solutions Germany GmbH, GF: Felix Imendörffer, HRB 36809, AG Nürnberg
^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: [PATCH] tools/power/turbostat: fix compatibility with older kernels
2021-01-27 18:59 ` Borislav Petkov
@ 2021-01-27 20:15 ` Doug Smythies
2021-01-27 20:33 ` Borislav Petkov
0 siblings, 1 reply; 6+ messages in thread
From: Doug Smythies @ 2021-01-27 20:15 UTC (permalink / raw)
To: 'Borislav Petkov', 'Artem Bityutskiy'
Cc: 'Rafael J. Wysocki', 'Len Brown',
'Linux PM Mailing List'
On 2021.01.27 Borislav Petkov wrote:
> On Wed, Jan 27, 2021 at 03:24:44PM +0200, Artem Bityutskiy wrote:
> > From: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
> >
> > Commit
> >
> > 6d6501d912a9 tools/power/turbostat: Read energy_perf_bias from sysfs
> >
> > added a useful EPB print by reading EPB from sysfs's 'energy_perf_bias' file.
> > However, older kernels, which do not necessarily have that sysfs file (e.g.,
> > Centos 7's stock kernel does not have it). As a result, turbostat fails with
> > older kernels.
> >
> > This patch fixes the problem by ignoring the sysfs file read errors.
> >
> > Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
> > ---
> > tools/power/x86/turbostat/turbostat.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
> > index 389ea5209a83..12e014f2c24b 100644
> > --- a/tools/power/x86/turbostat/turbostat.c
> > +++ b/tools/power/x86/turbostat/turbostat.c
> > @@ -1839,7 +1839,9 @@ int get_epb(int cpu)
> >
> > sprintf(path, "/sys/devices/system/cpu/cpu%d/power/energy_perf_bias", cpu);
> >
> > - fp = fopen_or_die(path, "r");
> > + fp = fopen(path, "r");
> > + if (!fp)
> > + return -1;
> >
> > ret = fscanf(fp, "%d", &epb);
> > if (ret != 1)
>
> So I was under the impression that things in tools/ are tied to the
> kernel version they're shipped with. Which means, you should probably
> get the one from the centos kernel.
>
> However, if this is supposed to work on older kernels too, then
It is supposed to work with old kernels. Here is a quote from Len from [1] (2019.09.05) :
> The latest turbostat and x86_energy_perf_policy utilities
> in the upstream kernel tree should always be backward
> compatible with all old kernels. If that is EVER not the
> case, I want to know about it.
>
> Yes, I know that some distros ship old versions of these
> utilities built out of their matching kernel tree snapshots.
> Yes, applying upstream fixes to .stable for such distros is a good thing.
>
> However, the better solution for these particular utilities, is that
> they simply always use upstream utilities -- even with old kernels.
>
> When somebody reports a problem and I need them to run these tools,
> 100% of the time, I start by sending them the latest upstream version
> to replace the old version shipped by the distro.
Which is also what I do. I was also trying, so far without success, to
get a distro to relax its stringent, unnecessary, turbostat dependency
checking [2].
>
> 6d6501d912a9 ("tools/power/turbostat: Read energy_perf_bias from sysfs")
>
> would need to be extended to first test the sysfs file's existence and
> if not there, fall back to the MSR reading...
Yes agree, the information is still required.
[1] https://marc.info/?l=linux-pm&m=156770359620861&w=2
[2] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1844201
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] tools/power/turbostat: fix compatibility with older kernels
2021-01-27 20:15 ` Doug Smythies
@ 2021-01-27 20:33 ` Borislav Petkov
2021-01-28 17:10 ` Borislav Petkov
0 siblings, 1 reply; 6+ messages in thread
From: Borislav Petkov @ 2021-01-27 20:33 UTC (permalink / raw)
To: Doug Smythies
Cc: 'Artem Bityutskiy', 'Rafael J. Wysocki',
'Len Brown', 'Linux PM Mailing List'
On Wed, Jan 27, 2021 at 12:15:10PM -0800, Doug Smythies wrote:
> It is supposed to work with old kernels. Here is a quote from Len from
> [1] (2019.09.05) :
Yeah, reportedly, this is the general strategy with tools in tools/.
> Which is also what I do. I was also trying, so far without success, to
> get a distro to relax its stringent, unnecessary, turbostat dependency
> checking [2].
I see.
> Yes agree, the information is still required.
Yeah, lemme do a proper patch tomorrow.
Thx.
--
Regards/Gruss,
Boris.
SUSE Software Solutions Germany GmbH, GF: Felix Imendörffer, HRB 36809, AG Nürnberg
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] tools/power/turbostat: fix compatibility with older kernels
2021-01-27 20:33 ` Borislav Petkov
@ 2021-01-28 17:10 ` Borislav Petkov
0 siblings, 0 replies; 6+ messages in thread
From: Borislav Petkov @ 2021-01-28 17:10 UTC (permalink / raw)
To: 'Artem Bityutskiy'
Cc: Doug Smythies, 'Rafael J. Wysocki', 'Len Brown',
'Linux PM Mailing List'
On Wed, Jan 27, 2021 at 09:33:46PM +0100, Borislav Petkov wrote:
> Yeah, lemme do a proper patch tomorrow.
Artem, how's that?
---
diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 389ea5209a83..a7c4f0772e53 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -1834,12 +1834,15 @@ int get_mp(int cpu, struct msr_counter *mp, unsigned long long *counterp)
int get_epb(int cpu)
{
char path[128 + PATH_BYTES];
+ unsigned long long msr;
int ret, epb = -1;
FILE *fp;
sprintf(path, "/sys/devices/system/cpu/cpu%d/power/energy_perf_bias", cpu);
- fp = fopen_or_die(path, "r");
+ fp = fopen(path, "r");
+ if (!fp)
+ goto msr_fallback;
ret = fscanf(fp, "%d", &epb);
if (ret != 1)
@@ -1848,6 +1851,11 @@ int get_epb(int cpu)
fclose(fp);
return epb;
+
+msr_fallback:
+ get_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, &msr);
+
+ return msr & 0xf;
}
void get_apic_id(struct thread_data *t)
---
Thx.
--
Regards/Gruss,
Boris.
SUSE Software Solutions Germany GmbH, GF: Felix Imendörffer, HRB 36809, AG Nürnberg
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [tip: x86/urgent] tools/power/turbostat: Fallback to an MSR read for EPB
2021-01-27 13:24 [PATCH] tools/power/turbostat: fix compatibility with older kernels Artem Bityutskiy
2021-01-27 18:59 ` Borislav Petkov
@ 2021-02-03 11:06 ` tip-bot2 for Borislav Petkov
1 sibling, 0 replies; 6+ messages in thread
From: tip-bot2 for Borislav Petkov @ 2021-02-03 11:06 UTC (permalink / raw)
To: linux-tip-commits; +Cc: Artem Bityutskiy, Borislav Petkov, x86, linux-kernel
The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: 7f1b11ba3564a391169420d98162987a12d0795d
Gitweb: https://git.kernel.org/tip/7f1b11ba3564a391169420d98162987a12d0795d
Author: Borislav Petkov <bp@suse.de>
AuthorDate: Thu, 28 Jan 2021 20:28:56 +01:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Wed, 03 Feb 2021 11:58:19 +01:00
tools/power/turbostat: Fallback to an MSR read for EPB
Commit
6d6501d912a9 ("tools/power/turbostat: Read energy_perf_bias from sysfs")
converted turbostat to read the energy_perf_bias value from sysfs.
However, older kernels which do not have that file yet, would fail. For
those, fall back to the MSR reading.
Fixes: 6d6501d912a9 ("tools/power/turbostat: Read energy_perf_bias from sysfs")
Reported-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Link: https://lkml.kernel.org/r/20210127132444.981120-1-dedekind1@gmail.com
---
tools/power/x86/turbostat/turbostat.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 389ea52..a7c4f07 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -1834,12 +1834,15 @@ int get_mp(int cpu, struct msr_counter *mp, unsigned long long *counterp)
int get_epb(int cpu)
{
char path[128 + PATH_BYTES];
+ unsigned long long msr;
int ret, epb = -1;
FILE *fp;
sprintf(path, "/sys/devices/system/cpu/cpu%d/power/energy_perf_bias", cpu);
- fp = fopen_or_die(path, "r");
+ fp = fopen(path, "r");
+ if (!fp)
+ goto msr_fallback;
ret = fscanf(fp, "%d", &epb);
if (ret != 1)
@@ -1848,6 +1851,11 @@ int get_epb(int cpu)
fclose(fp);
return epb;
+
+msr_fallback:
+ get_msr(cpu, MSR_IA32_ENERGY_PERF_BIAS, &msr);
+
+ return msr & 0xf;
}
void get_apic_id(struct thread_data *t)
^ permalink raw reply related [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-02-03 11:07 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-01-27 13:24 [PATCH] tools/power/turbostat: fix compatibility with older kernels Artem Bityutskiy
2021-01-27 18:59 ` Borislav Petkov
2021-01-27 20:15 ` Doug Smythies
2021-01-27 20:33 ` Borislav Petkov
2021-01-28 17:10 ` Borislav Petkov
2021-02-03 11:06 ` [tip: x86/urgent] tools/power/turbostat: Fallback to an MSR read for EPB tip-bot2 for Borislav Petkov
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