linux-kernel - Re: [PATCH v2 3/5] cpupower: Add EPP value change support

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Message-ID: <84f06212-b212-8bc7-d0f0-21b55a9bd3aa@amd.com>
Date:   Sun, 18 Jun 2023 20:58:54 -0500
From:   Mario Limonciello <mario.limonciello@....com>
To:     Wyes Karny <wyes.karny@....com>, trenn@...e.com, shuah@...nel.org
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        rafael@...nel.org, gautham.shenoy@....com, Ray.Huang@....com,
        Perry.Yuan@....com
Subject: Re: [PATCH v2 3/5] cpupower: Add EPP value change support

On 6/16/23 07:09, Wyes Karny 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@....com>
Reviewed-by: Mario Limonciello <mario.limonciello@....com>

> ---
>   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'},
>   	{ },
>   };
>   
> @@ -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);