Commit 7f1b11ba authored by Borislav Petkov's avatar Borislav Petkov
Browse files

tools/power/turbostat: Fallback to an MSR read for EPB 



Commit

  6d6501d9 ("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: 6d6501d9 ("tools/power/turbostat: Read energy_perf_bias from sysfs")
Reported-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Tested-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Link: https://lkml.kernel.org/r/20210127132444.981120-1-dedekind1@gmail.com
parent 8acf4178

tools/power/x86/turbostat/turbostat.c

+9 −1
Original line number Diff line number Diff line
@@ -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)