* [tip: x86/urgent] tools/power/turbostat: Fallback to an MSR read for EPB
[not found] <20210127132444.981120-1-dedekind1@gmail.com>
@ 2021-02-03 11:06 ` tip-bot2 for Borislav Petkov
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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)
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