linux-kernel - Re: [PATCH v2 3/4] cpufreq/amd-pstate: Update asym_prefer

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Message-ID: <f8a06d12-4728-43f3-a87f-35728e5d145c@amd.com>
Date: Wed, 9 Apr 2025 14:15:09 -0500
From: Mario Limonciello <mario.limonciello@....com>
To: K Prateek Nayak <kprateek.nayak@....com>, Ingo Molnar <mingo@...hat.com>,
 Peter Zijlstra <peterz@...radead.org>, Juri Lelli <juri.lelli@...hat.com>,
 Vincent Guittot <vincent.guittot@...aro.org>,
 "Gautham R. Shenoy" <gautham.shenoy@....com>,
 "Rafael J. Wysocki" <rafael@...nel.org>,
 Viresh Kumar <viresh.kumar@...aro.org>, linux-pm@...r.kernel.org,
 linux-kernel@...r.kernel.org
Cc: Dietmar Eggemann <dietmar.eggemann@....com>,
 Steven Rostedt <rostedt@...dmis.org>, Ben Segall <bsegall@...gle.com>,
 Mel Gorman <mgorman@...e.de>, Valentin Schneider <vschneid@...hat.com>,
 Waiman Long <llong@...hat.com>, Swapnil Sapkal <swapnil.sapkal@....com>,
 Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>, Huang Rui
 <ray.huang@....com>, Perry Yuan <perry.yuan@....com>
Subject: Re: [PATCH v2 3/4] cpufreq/amd-pstate: Update asym_prefer_cpu when
 core rankings change

On 4/9/2025 12:34 AM, K Prateek Nayak wrote:
> A subset of AMD systems supporting Preferred Core rankings can have
> their rankings changed dynamically at runtime. Update the
> "sg->asym_prefer_cpu" across the local hierarchy of CPU when the
> preferred core ranking changes.
> 
> Signed-off-by: K Prateek Nayak <kprateek.nayak@....com>
Acked-by: Mario Limonciello <mario.limonciello@....com>
> ---
>   drivers/cpufreq/amd-pstate.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 6789eed1bb5b..8796217ccc60 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -844,8 +844,10 @@ static void amd_pstate_update_limits(unsigned int cpu)
>   	if (highest_perf_changed) {
>   		WRITE_ONCE(cpudata->prefcore_ranking, cur_high);
>   
> -		if (cur_high < CPPC_MAX_PERF)
> +		if (cur_high < CPPC_MAX_PERF) {
>   			sched_set_itmt_core_prio((int)cur_high, cpu);
> +			sched_update_asym_prefer_cpu(cpu, prev_high, cur_high);
> +		}
>   	}
>   }
>