linux-kernel - Re: [PATCH v2 15/16] cpufreq/amd-pstate: Set different default EPP policy for Epyc and Ryzen

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Message-ID: <Z1a4HuUug8+4nSYp@BLRRASHENOY1.amd.com>
Date: Mon, 9 Dec 2024 14:57:58 +0530
From: "Gautham R. Shenoy" <gautham.shenoy@....com>
To: Mario Limonciello <mario.limonciello@....com>
Cc: Perry Yuan <perry.yuan@....com>, linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org,
	Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>,
	"Artem S . Tashkinov" <aros@....com>
Subject: Re: [PATCH v2 15/16] cpufreq/amd-pstate: Set different default EPP
 policy for Epyc and Ryzen

On Sun, Dec 08, 2024 at 12:30:30AM -0600, Mario Limonciello wrote:
> For Ryzen systems the EPP policy set by the BIOS is generally configured
> to performance as this is the default register value for the CPPC request
> MSR.
> 
> If a user doesn't use additional software to configure EPP then the system
> will default biased towards performance and consume extra battery. Instead
> configure the default to "balanced_performance" for this case.
> 
> Suggested-by: Artem S. Tashkinov <aros@....com>
> Reviewed-by: Dhananjay Ugwekar <dhananjay.ugwekar@....com>
> Tested-by: Dhananjay Ugwekar <dhananjay.ugwekar@....com>
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219526
> Reviewed-by: Gautham R. Shenoy <gautham.shenoy@....com>
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>

Looks good to me for EPYC.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@....com>

--
Thanks and Regards
gautham.

> ---
>  drivers/cpufreq/amd-pstate.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 5869bcd287e87..a4ededb8d89df 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -1501,8 +1501,6 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
>  
>  	policy->driver_data = cpudata;
>  
> -	cpudata->epp_cached = cpudata->epp_default = amd_pstate_get_epp(cpudata);
> -
>  	policy->min = policy->cpuinfo.min_freq;
>  	policy->max = policy->cpuinfo.max_freq;
>  
> @@ -1513,10 +1511,13 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
>  	 * the default cpufreq governor is neither powersave nor performance.
>  	 */
>  	if (amd_pstate_acpi_pm_profile_server() ||
> -	    amd_pstate_acpi_pm_profile_undefined())
> +	    amd_pstate_acpi_pm_profile_undefined()) {
>  		policy->policy = CPUFREQ_POLICY_PERFORMANCE;
> -	else
> +		cpudata->epp_default = amd_pstate_get_epp(cpudata);
> +	} else {
>  		policy->policy = CPUFREQ_POLICY_POWERSAVE;
> +		cpudata->epp_default = AMD_CPPC_EPP_BALANCE_PERFORMANCE;
> +	}
>  
>  	if (cpu_feature_enabled(X86_FEATURE_CPPC)) {
>  		ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, &value);
> @@ -1529,6 +1530,9 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
>  			return ret;
>  		WRITE_ONCE(cpudata->cppc_cap1_cached, value);
>  	}
> +	ret = amd_pstate_set_epp(cpudata, cpudata->epp_default);
> +	if (ret)
> +		return ret;
>  
>  	current_pstate_driver->adjust_perf = NULL;
>  
> -- 
> 2.43.0
>