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authorBorislav Petkov <bp@suse.de>2021-01-28 20:28:56 +0100
committerBorislav Petkov <bp@suse.de>2021-02-03 11:58:19 +0100
commit7f1b11ba3564a391169420d98162987a12d0795d (patch)
tree3b2563f7b5e3e8edaf41a7cc7d015f82fbb5a1ed
parent8acf417805a5f5c69e9ff66f14cab022c2755161 (diff)
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
-rw-r--r--tools/power/x86/turbostat/turbostat.c10
1 files changed, 9 insertions, 1 deletions
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)