Messages in this thread | | | Date | Mon, 13 Sep 2021 19:29:45 +0800 | From | Huang Rui <> | Subject | Re: [PATCH 13/19] cpupower: add the function to check amd-pstate enabled |
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On Fri, Sep 10, 2021 at 06:16:21AM +0800, Shuah Khan wrote: > On 9/8/21 8:59 AM, Huang Rui wrote: > > Introduce the cpupower_amd_pstate_enabled() to check whether the kernel > > mode enables amd-pstate. > > > > What does "kernel mode" mean? Are you referring to kernel vs. > firmware mode?
I am referring kernel. In fact, the proccessor which supports the AMD P-States also supports the legacy ACPI P-States as well. So this API is to check whether the kernel driver is using amd-pstate or acpi-cpufreq.
I would have explained this, sorry to make you confused, I will explain the details in the commit log at V2.
Thanks, Ray
> > > Signed-off-by: Huang Rui <ray.huang@amd.com> > > --- > > tools/power/cpupower/utils/helpers/helpers.h | 5 +++++ > > tools/power/cpupower/utils/helpers/misc.c | 20 ++++++++++++++++++++ > > 2 files changed, 25 insertions(+) > > > > diff --git a/tools/power/cpupower/utils/helpers/helpers.h b/tools/power/cpupower/utils/helpers/helpers.h > > index b4813efdfb00..eb43c14d1728 100644 > > --- a/tools/power/cpupower/utils/helpers/helpers.h > > +++ b/tools/power/cpupower/utils/helpers/helpers.h > > @@ -136,6 +136,11 @@ extern int decode_pstates(unsigned int cpu, int boost_states, > > > > extern int cpufreq_has_boost_support(unsigned int cpu, int *support, > > int *active, int * states); > > + > > +/* AMD PSTATE enabling **************************/ > > + > > +extern unsigned long cpupower_amd_pstate_enabled(unsigned int cpu); > > + > > /* > > * CPUID functions returning a single datum > > */ > > diff --git a/tools/power/cpupower/utils/helpers/misc.c b/tools/power/cpupower/utils/helpers/misc.c > > index fc6e34511721..07d80775fb68 100644 > > --- a/tools/power/cpupower/utils/helpers/misc.c > > +++ b/tools/power/cpupower/utils/helpers/misc.c > > @@ -83,6 +83,26 @@ int cpupower_intel_set_perf_bias(unsigned int cpu, unsigned int val) > > return 0; > > } > > > > +unsigned long cpupower_amd_pstate_enabled(unsigned int cpu) > > +{ > > + char linebuf[MAX_LINE_LEN]; > > + char path[SYSFS_PATH_MAX]; > > + unsigned long val; > > + char *endp; > > + > > + snprintf(path, sizeof(path), > > + PATH_TO_CPU "cpu%u/cpufreq/is_amd_pstate_enabled", cpu); > > + > > + if (cpupower_read_sysfs(path, linebuf, MAX_LINE_LEN) == 0) > > + return 0; > > + > > + val = strtoul(linebuf, &endp, 0); > > + if (endp == linebuf || errno == ERANGE) > > + return 0; > > + > > + return val; > > +} > > + > > #endif /* #if defined(__i386__) || defined(__x86_64__) */ > > > > /* get_cpustate > > >
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