Re: [PATCH v10 3/7] cpufreq: amd-pstate: implement cpb_boost sysfs entry for boost control

[Oleksandr Natalenko <oleksandr@natalenko.name>]

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Hello.

On středa 8. května 2024 9:21:08, SELČ Perry Yuan wrote:
> From: Perry Yuan <Perry.Yuan@amd.com>
> 
> With this new sysfs entry `cpb_boost`created, user can change CPU boost
> state dynamically under `active`, `guided` and `passive` modes.
> And the highest perf and frequency will also be updated as the boost
> state changing.
> 
> 0): check current boost state
> cat /sys/devices/system/cpu/amd_pstate/cpb_boost
> 
> 1): disable CPU boost
> sudo bash -c "echo 0 > /sys/devices/system/cpu/amd_pstate/cpb_boost"
> 
> 2): enable CPU boost
> sudo bash -c "echo 1 > /sys/devices/system/cpu/amd_pstate/cpb_boost"
> 
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=217931
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=217618
> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> ---
>  drivers/cpufreq/amd-pstate-ut.c |   2 +-
>  drivers/cpufreq/amd-pstate.c    | 114 +++++++++++++++++++++++++++++++-
>  include/linux/amd-pstate.h      |   1 +
>  3 files changed, 115 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cpufreq/amd-pstate-ut.c b/drivers/cpufreq/amd-pstate-ut.c
> index f04ae67dda37..b3601b0e6dd3 100644
> --- a/drivers/cpufreq/amd-pstate-ut.c
> +++ b/drivers/cpufreq/amd-pstate-ut.c
> @@ -226,7 +226,7 @@ static void amd_pstate_ut_check_freq(u32 index)
>  			goto skip_test;
>  		}
>  
> -		if (cpudata->boost_supported) {
> +		if (amd_pstate_global_params.cpb_boost) {
>  			if ((policy->max == cpudata->max_freq) ||
>  					(policy->max == cpudata->nominal_freq))
>  				amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_PASS;
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index f7dab0f7b452..f81fd61dd2a9 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -686,8 +686,10 @@ static int amd_pstate_boost_init(struct amd_cpudata *cpudata)
>  	}
>  
>  	amd_pstate_global_params.cpb_supported = !(boost_val & MSR_K7_HWCR_CPB_DIS);
> -	if (amd_pstate_global_params.cpb_supported)
> +	if (amd_pstate_global_params.cpb_supported) {
>  		current_pstate_driver->boost_enabled = true;
> +		cpudata->boost_state = true;
> +	}
>  
>  	amd_pstate_global_params.cpb_boost = amd_pstate_global_params.cpb_supported;
>  
> @@ -1293,6 +1295,114 @@ static ssize_t prefcore_show(struct device *dev,
>  	return sysfs_emit(buf, "%s\n", str_enabled_disabled(amd_pstate_prefcore));
>  }
>  
> +static int amd_pstate_cpu_boost_update(struct cpufreq_policy *policy, bool on)
> +{
> +	struct amd_cpudata *cpudata = policy->driver_data;
> +	struct cppc_perf_ctrls perf_ctrls;
> +	u32 highest_perf, nominal_perf, nominal_freq, max_freq;
> +	int ret;
> +
> +	if (!policy) {
> +		pr_err("policy is null\n");
> +		return -ENODATA;
> +	}
> +
> +	highest_perf = READ_ONCE(cpudata->highest_perf);
> +	nominal_perf = READ_ONCE(cpudata->nominal_perf);
> +	nominal_freq = READ_ONCE(cpudata->nominal_freq);
> +	max_freq = READ_ONCE(cpudata->max_freq);
> +
> +	if (boot_cpu_has(X86_FEATURE_CPPC)) {
> +		u64 value = READ_ONCE(cpudata->cppc_req_cached);
> +
> +		value &= ~GENMASK_ULL(7, 0);
> +		value |= on ? highest_perf : nominal_perf;
> +		WRITE_ONCE(cpudata->cppc_req_cached, value);
> +
> +		wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
> +	} else {
> +		perf_ctrls.max_perf = on ? highest_perf : nominal_perf;
> +		ret = cppc_set_epp_perf(cpudata->cpu, &perf_ctrls, 1);
> +		if (ret) {
> +			cpufreq_cpu_release(policy);
> +			pr_debug("failed to set energy perf value (%d)\n", ret);
> +			return ret;
> +		}
> +	}
> +
> +	if (on)
> +		policy->cpuinfo.max_freq = max_freq;
> +	else
> +		policy->cpuinfo.max_freq = nominal_freq * 1000;
> +
> +	policy->max = policy->cpuinfo.max_freq;
> +
> +	if (cppc_state == AMD_PSTATE_PASSIVE) {
> +		ret = freq_qos_update_request(&cpudata->req[1],
> +				      policy->cpuinfo.max_freq);
> +	}
> +
> +	return ret;
> +}
> +
> +static int amd_pstate_cpu_boost(int cpu, bool state)
> +{
> +	int ret;
> +	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
> +	struct amd_cpudata *cpudata = policy->driver_data;
> +
> +	if (!policy) {
> +		pr_err("policy is NULL\n");
> +		ret = -ENODATA;
> +		goto err_exit;
> +	}
> +
> +	ret = amd_pstate_cpu_boost_update(policy, state);
> +	refresh_frequency_limits(policy);
> +	cpudata->boost_state = !!state;
> +
> +err_exit:
> +	cpufreq_cpu_put(policy);
> +	return ret < 0 ? ret : 0;
> +}
> +
> +static ssize_t cpb_boost_show(struct device *dev,
> +			   struct device_attribute *attr, char *buf)
> +{
> +	return sysfs_emit(buf, "%u\n", amd_pstate_global_params.cpb_boost);
> +}
> +
> +static ssize_t cpb_boost_store(struct device *dev, struct device_attribute *b,
> +			    const char *buf, size_t count)
> +{
> +	bool new_state;
> +	ssize_t ret;
> +	int cpu;
> +
> +	if (!amd_pstate_global_params.cpb_supported) {
> +		pr_err("Boost mode is not supported by this processor or SBIOS\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = kstrtobool(buf, &new_state);
> +	if (ret)
> +		return ret;
> +
> +	mutex_lock(&amd_pstate_driver_lock);
> +	for_each_present_cpu(cpu) {
> +		ret = amd_pstate_cpu_boost(cpu, new_state);
> +		if (ret < 0) {
> +			pr_warn("failed to update cpu boost for CPU%d (%d)\n", cpu, ret);

Note ret is ssize_t, so %d should be %ld (or %z/%zd/%zi?) instead.

> +			goto err_exit;
> +		}
> +	}
> +	amd_pstate_global_params.cpb_boost = !!new_state;
> +
> +err_exit:
> +	mutex_unlock(&amd_pstate_driver_lock);
> +	return ret < 0 ? ret : count;
> +}
> +
>  cpufreq_freq_attr_ro(amd_pstate_max_freq);
>  cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
>  
> @@ -1303,6 +1413,7 @@ cpufreq_freq_attr_rw(energy_performance_preference);
>  cpufreq_freq_attr_ro(energy_performance_available_preferences);
>  static DEVICE_ATTR_RW(status);
>  static DEVICE_ATTR_RO(prefcore);
> +static DEVICE_ATTR_RW(cpb_boost);
>  
>  static struct freq_attr *amd_pstate_attr[] = {
>  	&amd_pstate_max_freq,
> @@ -1327,6 +1438,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
>  static struct attribute *pstate_global_attributes[] = {
>  	&dev_attr_status.attr,
>  	&dev_attr_prefcore.attr,
> +	&dev_attr_cpb_boost.attr,
>  	NULL
>  };
>  
> diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
> index 8ba5dd4d3405..56f616a5cd0f 100644
> --- a/include/linux/amd-pstate.h
> +++ b/include/linux/amd-pstate.h
> @@ -106,6 +106,7 @@ struct amd_cpudata {
>  	u32	policy;
>  	u64	cppc_cap1_cached;
>  	bool	suspended;
> +	bool	boost_state;
>  };
>  
>  /*
> 


-- 
Oleksandr Natalenko (post-factum)

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