linux-kernel - Re: [RFC/RFT] [PATCH 06/10] cpufreq / sched: Add interface to get utilization values

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Message-ID: <20180516081155.GA12217@hirez.programming.kicks-ass.net>
Date:   Wed, 16 May 2018 10:11:55 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Cc:     tglx@...utronix.de, mingo@...hat.com, bp@...e.de, lenb@...nel.org,
        rjw@...ysocki.net, mgorman@...hsingularity.net, x86@...nel.org,
        linux-pm@...r.kernel.org, viresh.kumar@...aro.org,
        juri.lelli@....com, linux-kernel@...r.kernel.org
Subject: Re: [RFC/RFT] [PATCH 06/10] cpufreq / sched: Add interface to get
 utilization values

On Tue, May 15, 2018 at 09:49:07PM -0700, Srinivas Pandruvada wrote:
> --- a/kernel/sched/cpufreq.c
> +++ b/kernel/sched/cpufreq.c
> @@ -60,3 +60,26 @@ void cpufreq_remove_update_util_hook(int cpu)
>  	rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), NULL);
>  }
>  EXPORT_SYMBOL_GPL(cpufreq_remove_update_util_hook);
> +
> +/**
> + * cpufreq_get_sched_util - Get utilization values.
> + * @cpu: The targeted CPU.
> + *
> + * Get the CFS, DL and max utilization.
> + * This function allows cpufreq driver outside the kernel/sched to access
> + * utilization value for a CPUs run queue.
> + */
> +void cpufreq_get_sched_util(int cpu, unsigned long *util_cfs,
> +			    unsigned long *util_dl, unsigned long *max)
> +{
> +#ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL
> +	struct rq *rq = cpu_rq(cpu);
> +
> +	*max = arch_scale_cpu_capacity(NULL, cpu);
> +	*util_cfs = cpu_util_cfs(rq);
> +	*util_dl  = cpu_util_dl(rq);
> +#else
> +	*util_cfs = *util_dl = 1;
> +#endif
> +}
> +EXPORT_SYMBOL_GPL(cpufreq_get_sched_util);

So I _really_ hate this... I'd much rather you make schedutil work with
the hwp passive stuff.

Also, afaict intel_pstate is bool, not tristate, so no need for an
EXPORT at all.