Re: [PATCH 4/6] cpupower: Add EPP value change support

[Wyes Karny]

Hi Ray,

On 16 Jun 15:22, Huang Rui wrote:
> On Mon, Jun 12, 2023 at 07:36:13PM +0800, Karny, Wyes wrote:
> > amd_pstate and intel_pstate active mode drivers support energy
> > performance preference feature. Through this user can convey it's
> > energy/performance preference to platform. Add this value change
> > capability to cpupower.
> > 
> > To change the EPP value use below command:
> > cpupower set --epp performance
> > 
> > Signed-off-by: Wyes Karny <wyes.karny@xxxxxxx>
> > ---
> >  tools/power/cpupower/utils/cpupower-set.c    | 23 +++++++++++++++++++-
> >  tools/power/cpupower/utils/helpers/helpers.h |  5 +++++
> >  tools/power/cpupower/utils/helpers/misc.c    | 19 ++++++++++++++++
> >  3 files changed, 46 insertions(+), 1 deletion(-)
> > 
> > diff --git a/tools/power/cpupower/utils/cpupower-set.c b/tools/power/cpupower/utils/cpupower-set.c
> > index 180d5ba877e6..a789b123dbd4 100644
> > --- a/tools/power/cpupower/utils/cpupower-set.c
> > +++ b/tools/power/cpupower/utils/cpupower-set.c
> > @@ -18,6 +18,7 @@
> >  
> >  static struct option set_opts[] = {
> >  	{"perf-bias", required_argument, NULL, 'b'},
> > +	{"epp", required_argument, NULL, 'e'},
> 
> How about re-using the "perf-bias", I think it should be the simliar
> function with Intel's processor?

AFAIU 'perf-bias' is not same as 'epp'. Perf-bias sysfs file expects
0-15 integer value, whereas epp sysfs file expects one of the string
form energy_performance_available_preferences file.

Thanks,
Wyes
> 
> Thanks,
> Ray
> 
> >  	{ },
> >  };
> >  
> > @@ -37,11 +38,13 @@ int cmd_set(int argc, char **argv)
> >  	union {
> >  		struct {
> >  			int perf_bias:1;
> > +			int epp:1;
> >  		};
> >  		int params;
> >  	} params;
> >  	int perf_bias = 0;
> >  	int ret = 0;
> > +	char epp[30];
> >  
> >  	ret = uname(&uts);
> >  	if (!ret && (!strcmp(uts.machine, "ppc64le") ||
> > @@ -55,7 +58,7 @@ int cmd_set(int argc, char **argv)
> >  
> >  	params.params = 0;
> >  	/* parameter parsing */
> > -	while ((ret = getopt_long(argc, argv, "b:",
> > +	while ((ret = getopt_long(argc, argv, "b:e:",
> >  						set_opts, NULL)) != -1) {
> >  		switch (ret) {
> >  		case 'b':
> > @@ -69,6 +72,15 @@ int cmd_set(int argc, char **argv)
> >  			}
> >  			params.perf_bias = 1;
> >  			break;
> > +		case 'e':
> > +			if (params.epp)
> > +				print_wrong_arg_exit();
> > +			if (sscanf(optarg, "%29s", epp) != 1) {
> > +				print_wrong_arg_exit();
> > +				return -EINVAL;
> > +			}
> > +			params.epp = 1;
> > +			break;
> >  		default:
> >  			print_wrong_arg_exit();
> >  		}
> > @@ -102,6 +114,15 @@ int cmd_set(int argc, char **argv)
> >  				break;
> >  			}
> >  		}
> > +
> > +		if (params.epp) {
> > +			ret = cpupower_set_epp(cpu, epp);
> > +			if (ret) {
> > +				fprintf(stderr,
> > +					"Error setting epp value on CPU %d\n", cpu);
> > +				break;
> > +			}
> > +		}
> >  	}
> >  	return ret;
> >  }
> > diff --git a/tools/power/cpupower/utils/helpers/helpers.h b/tools/power/cpupower/utils/helpers/helpers.h
> > index 96e4bede078b..5d998de2d291 100644
> > --- a/tools/power/cpupower/utils/helpers/helpers.h
> > +++ b/tools/power/cpupower/utils/helpers/helpers.h
> > @@ -116,6 +116,8 @@ extern int cpupower_intel_set_perf_bias(unsigned int cpu, unsigned int val);
> >  extern int cpupower_intel_get_perf_bias(unsigned int cpu);
> >  extern unsigned long long msr_intel_get_turbo_ratio(unsigned int cpu);
> >  
> > +extern int cpupower_set_epp(unsigned int cpu, char *epp);
> > +
> >  /* Read/Write msr ****************************/
> >  
> >  /* PCI stuff ****************************/
> > @@ -173,6 +175,9 @@ static inline int cpupower_intel_get_perf_bias(unsigned int cpu)
> >  static inline unsigned long long msr_intel_get_turbo_ratio(unsigned int cpu)
> >  { return 0; };
> >  
> > +static inline int cpupower_set_epp(unsigned int cpu, char *epp)
> > +{ return -1; };
> > +
> >  /* Read/Write msr ****************************/
> >  
> >  static inline int cpufreq_has_boost_support(unsigned int cpu, int *support,
> > diff --git a/tools/power/cpupower/utils/helpers/misc.c b/tools/power/cpupower/utils/helpers/misc.c
> > index 21f653cd472c..63c3f26ef874 100644
> > --- a/tools/power/cpupower/utils/helpers/misc.c
> > +++ b/tools/power/cpupower/utils/helpers/misc.c
> > @@ -87,6 +87,25 @@ int cpupower_intel_set_perf_bias(unsigned int cpu, unsigned int val)
> >  	return 0;
> >  }
> >  
> > +int cpupower_set_epp(unsigned int cpu, char *epp)
> > +{
> > +	char path[SYSFS_PATH_MAX];
> > +	char linebuf[30] = {};
> > +
> > +	snprintf(path, sizeof(path),
> > +		PATH_TO_CPU "cpu%u/cpufreq/energy_performance_preference", cpu);
> > +
> > +	if (!is_valid_path(path))
> > +		return -1;
> > +
> > +	snprintf(linebuf, sizeof(linebuf), "%s", epp);
> > +
> > +	if (cpupower_write_sysfs(path, linebuf, 30) <= 0)
> > +		return -1;
> > +
> > +	return 0;
> > +}
> > +
> >  bool cpupower_amd_pstate_enabled(void)
> >  {
> >  	char *driver = cpufreq_get_driver(0);
> > -- 
> > 2.34.1
> >