linux-kernel - Re: [PATCH v3 0/6] cpufreq: schedutil: fixes for flags updates

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Date:   Wed, 20 Dec 2017 16:43:58 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Patrick Bellasi <patrick.bellasi@....com>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        Ingo Molnar <mingo@...hat.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Morten Rasmussen <morten.rasmussen@....com>,
        Juri Lelli <juri.lelli@...hat.com>,
        Todd Kjos <tkjos@...roid.com>,
        Joel Fernandes <joelaf@...gle.com>
Subject: Re: [PATCH v3 0/6] cpufreq: schedutil: fixes for flags updates

On Wed, Dec 20, 2017 at 04:30:29PM +0100, Peter Zijlstra wrote:
> @@ -314,6 +315,9 @@ static unsigned int sugov_next_freq_shar
>  		unsigned long j_util, j_max;
>  		s64 delta_ns;
>  
> +		if (j_sg_cpu != sg_cpu)
> +			sugov_get_util(j_sg_cpu);
> +
>  		/*
>  		 * If the CFS CPU utilization was last updated before the
>  		 * previous frequency update and the time elapsed between the
> @@ -327,12 +331,7 @@ static unsigned int sugov_next_freq_shar
>  		if (delta_ns > TICK_NSEC) {
>  			j_sg_cpu->iowait_boost = 0;
>  			j_sg_cpu->iowait_boost_pending = false;
> -			j_sg_cpu->util_cfs = 0;
> -			if (j_sg_cpu->util_dl == 0)
> -				continue;
>  		}
> -		if (j_sg_cpu->flags & SCHED_CPUFREQ_RT)
> -			return policy->cpuinfo.max_freq;
>  
>  		j_max = j_sg_cpu->max;
>  		j_util = sugov_aggregate_util(j_sg_cpu);

The below makes more sense to me too; hmm?

@@ -335,12 +335,11 @@ static unsigned int sugov_next_freq_shar
 
 		j_max = j_sg_cpu->max;
 		j_util = sugov_aggregate_util(j_sg_cpu);
+		sugov_iowait_boost(j_sg_cpu, &util, &max);
 		if (j_util * max > j_max * util) {
 			util = j_util;
 			max = j_max;
 		}
-
-		sugov_iowait_boost(j_sg_cpu, &util, &max);
 	}
 
 	return get_next_freq(sg_policy, util, max);