linux-kernel - Re: [PATCH v4 3/7] cpufreq: amd-pstate: fix max_perf calculation for amd_get_max

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Date: Thu, 14 Mar 2024 15:13:21 +0530
From: "Gautham R. Shenoy" <gautham.shenoy@....com>
To: Perry Yuan <perry.yuan@....com>
Cc: rafael.j.wysocki@...el.com, Mario.Limonciello@....com,
	viresh.kumar@...aro.org, Ray.Huang@....com, Borislav.Petkov@....com,
	Alexander.Deucher@....com, Xinmei.Huang@....com,
	Xiaojian.Du@....com, Li.Meng@....com, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 3/7] cpufreq: amd-pstate: fix max_perf calculation for
 amd_get_max_freq()

On Wed, Mar 13, 2024 at 06:04:40PM +0800, Perry Yuan wrote:
> From: Perry Yuan <Perry.Yuan@....com>
> 
> When CPU core Precision Boost state changed, the max frequency will also
> need to be updated according to the current boost state, if boost is
> disabled now, the max perf will be limited to nominal perf values.
> otherwise the max frequency will be showed wrongly.
> 
> Signed-off-by: Perry Yuan <Perry.Yuan@....com>

Looks good to me.

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

> ---
>  drivers/cpufreq/amd-pstate.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index d54399ebb758..0965fbf660dd 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -632,6 +632,10 @@ static int amd_get_max_freq(struct amd_cpudata *cpudata)
>  	nominal_perf = READ_ONCE(cpudata->nominal_perf);
>  	max_perf = READ_ONCE(cpudata->highest_perf);
>  
> +	/* when boost is off, the highest perf will be limited to nominal_perf */
> +	if (!amd_pstate_global_params.cpb_boost)
> +		max_perf = nominal_perf;
> +
>  	boost_ratio = div_u64(max_perf << SCHED_CAPACITY_SHIFT,
>  			      nominal_perf);
>  
> -- 
> 2.34.1
>