Re: [PATCH] cpupower: Add intel_pstate turbo boost support for Intel platforms

[Zhang, Rui]

On Mon, 2026-02-09 at 11:24 +0800, Zhang Rui wrote:
> On modern Intel platforms, the intel_pstate driver is commonly used
> and
> it provides turbo boost control via
> /sys/devices/system/cpu/intel_pstate/no_turbo.
> 
> However, cpupower doesn't handle this. it
> 1. shows turbo boost as "active" blindly for Intel platforms
> 2. controls turbo boost functionality via the generic
>    /sys/devices/system/cpu/cpufreq/boost sysfs interface only.
> 
> Enhance the cpupower tool to ensure the "--boost" command works
> seamlessly on Intel platforms with intel_pstate driver running.
> 
Hi, Shuah,

can you please kindly check if this is a valid enhancement?

thanks,
rui

> Without this patch,
>    $ echo 1 | sudo tee /sys/devices/system/cpu/intel_pstate/no_turbo
>    1
>    $ sudo cpupower frequency-info --boost
>    analyzing CPU 21:
>      boost state support:
>        Supported: yes
>        Active: yes
>    $ sudo cpupower set --boost 0
>    Error setting turbo-boost
>    $ sudo cpupower set --boost 1
>    Error setting turbo-boost
> 
> With this patch,
>    $ cat /sys/devices/system/cpu/intel_pstate/no_turbo
>    0
>    $ sudo cpupower set --boost 0
>    $ sudo cpupower frequency-info --boost
>    analyzing CPU 21:
>      boost state support:
>        Supported: yes
>        Active: no
>    $ cat /sys/devices/system/cpu/intel_pstate/no_turbo
>    1
>    $ sudo cpupower set --boost 1
>    $ sudo cpupower frequency-info --boost
>    analyzing CPU 28:
>      boost state support:
>        Supported: yes
>        Active: yes
>    $ cat /sys/devices/system/cpu/intel_pstate/no_turbo
>    0
> 
> Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
> ---
>  tools/power/cpupower/utils/cpupower-set.c    |  6 ++-
>  tools/power/cpupower/utils/helpers/helpers.h |  5 ++-
>  tools/power/cpupower/utils/helpers/misc.c    | 41
> +++++++++++++++++++-
>  3 files changed, 48 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/power/cpupower/utils/cpupower-set.c
> b/tools/power/cpupower/utils/cpupower-set.c
> index c2117e5650dd..550a942e72ce 100644
> --- a/tools/power/cpupower/utils/cpupower-set.c
> +++ b/tools/power/cpupower/utils/cpupower-set.c
> @@ -124,7 +124,11 @@ int cmd_set(int argc, char **argv)
>  	}
>  
>  	if (params.turbo_boost) {
> -		ret = cpupower_set_turbo_boost(turbo_boost);
> +		if (cpupower_cpu_info.vendor == X86_VENDOR_INTEL)
> +			ret =
> cpupower_set_intel_turbo_boost(turbo_boost);
> +		else
> +			ret =
> cpupower_set_generic_turbo_boost(turbo_boost);
> +
>  		if (ret)
>  			fprintf(stderr, "Error setting turbo-
> boost\n");
>  	}
> diff --git a/tools/power/cpupower/utils/helpers/helpers.h
> b/tools/power/cpupower/utils/helpers/helpers.h
> index 82ea62bdf5a2..a3ad80b9c2c2 100644
> --- a/tools/power/cpupower/utils/helpers/helpers.h
> +++ b/tools/power/cpupower/utils/helpers/helpers.h
> @@ -104,7 +104,7 @@ extern struct cpupower_cpu_info
> cpupower_cpu_info;
>  /* cpuid and cpuinfo helpers  **************************/
>  
>  int cpufreq_has_generic_boost_support(bool *active);
> -int cpupower_set_turbo_boost(int turbo_boost);
> +int cpupower_set_generic_turbo_boost(int turbo_boost);
>  
>  /* X86 ONLY ****************************************/
>  #if defined(__i386__) || defined(__x86_64__)
> @@ -143,6 +143,7 @@ extern int decode_pstates(unsigned int cpu, int
> boost_states,
>  
>  int cpufreq_has_x86_boost_support(unsigned int cpu, int *support,
>  				  int *active, int *states);
> +int cpupower_set_intel_turbo_boost(int turbo_boost);
>  
>  /* AMD P-State stuff **************************/
>  bool cpupower_amd_pstate_enabled(void);
> @@ -189,6 +190,8 @@ static inline int
> cpupower_set_amd_pstate_mode(char *mode)
>  static inline int cpufreq_has_x86_boost_support(unsigned int cpu,
> int *support,
>  						int *active, int
> *states)
>  { return -1; }
> +static inline int cpupower_set_intel_turbo_boost(int turbo_boost)
> +{ return -1; }
>  
>  static inline bool cpupower_amd_pstate_enabled(void)
>  { return false; }
> diff --git a/tools/power/cpupower/utils/helpers/misc.c
> b/tools/power/cpupower/utils/helpers/misc.c
> index 166dc1e470ea..eebfc79a4889 100644
> --- a/tools/power/cpupower/utils/helpers/misc.c
> +++ b/tools/power/cpupower/utils/helpers/misc.c
> @@ -19,6 +19,9 @@ int cpufreq_has_x86_boost_support(unsigned int cpu,
> int *support, int *active,
>  {
>  	int ret;
>  	unsigned long long val;
> +	char linebuf[MAX_LINE_LEN];
> +	char path[SYSFS_PATH_MAX];
> +	char *endp;
>  
>  	*support = *active = *states = 0;
>  
> @@ -42,8 +45,42 @@ int cpufreq_has_x86_boost_support(unsigned int
> cpu, int *support, int *active,
>  		}
>  	} else if (cpupower_cpu_info.caps & CPUPOWER_CAP_AMD_PSTATE)
> {
>  		amd_pstate_boost_init(cpu, support, active);
> -	} else if (cpupower_cpu_info.caps & CPUPOWER_CAP_INTEL_IDA)
> +	} else if (cpupower_cpu_info.caps & CPUPOWER_CAP_INTEL_IDA)
> {
>  		*support = *active = 1;
> +
> +		snprintf(path, sizeof(path), PATH_TO_CPU
> "intel_pstate/no_turbo");
> +
> +		if (!is_valid_path(path))
> +			return 0;
> +
> +		if (cpupower_read_sysfs(path, linebuf, MAX_LINE_LEN)
> == 0)
> +			return -1;
> +
> +		val = strtol(linebuf, &endp, 0);
> +		if (endp == linebuf || errno == ERANGE)
> +			return -1;
> +
> +		*active = !val;
> +	}
> +	return 0;
> +}
> +
> +int cpupower_set_intel_turbo_boost(int turbo_boost)
> +{
> +	char path[SYSFS_PATH_MAX];
> +	char linebuf[2] = {};
> +
> +	snprintf(path, sizeof(path), PATH_TO_CPU
> "intel_pstate/no_turbo");
> +
> +	/* Fallback to generic solution when intel_pstate driver not
> running */
> +	if (!is_valid_path(path))
> +		return
> cpupower_set_generic_turbo_boost(turbo_boost);
> +
> +	snprintf(linebuf, sizeof(linebuf), "%d", !turbo_boost);
> +
> +	if (cpupower_write_sysfs(path, linebuf, 2) <= 0)
> +		return -1;
> +
>  	return 0;
>  }
>  
> @@ -274,7 +311,7 @@ void print_speed(unsigned long speed, int
> no_rounding)
>  	}
>  }
>  
> -int cpupower_set_turbo_boost(int turbo_boost)
> +int cpupower_set_generic_turbo_boost(int turbo_boost)
>  {
>  	char path[SYSFS_PATH_MAX];
>  	char linebuf[2] = {};