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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Steve Muckle <steve.muckle@linaro.org>,
	Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Juri Lelli <Juri.Lelli@arm.com>,
	Patrick Bellasi <patrick.bellasi@arm.com>,
	Steve Muckle <smuckle@linaro.org>
Subject: Re: [PATCH 1/2] sched: cpufreq: ignore SMT when determining max cpu capacity
Date: Wed, 31 Aug 2016 03:27:30 +0200	[thread overview]
Message-ID: <2411837.FJm8ec21FH@vostro.rjw.lan> (raw)
In-Reply-To: <1472236848-17038-2-git-send-email-smuckle@linaro.org>

On Friday, August 26, 2016 11:40:47 AM Steve Muckle wrote:
> PELT does not consider SMT when scaling its utilization values via
> arch_scale_cpu_capacity(). The value in rq->cpu_capacity_orig does
> take SMT into consideration though and therefore may be smaller than
> the utilization reported by PELT.
> 
> On an Intel i7-3630QM for example rq->cpu_capacity_orig is 589 but
> util_avg scales up to 1024. This means that a 50% utilized CPU will show
> up in schedutil as ~86% busy.
> 
> Fix this by using the same CPU scaling value in schedutil as that which
> is used by PELT.
> 
> Signed-off-by: Steve Muckle <smuckle@linaro.org>

This is fine by me.

Peter, any objections?

> ---
>  kernel/sched/cpufreq_schedutil.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> index 60d985f4dc47..cb8a77b1ef1b 100644
> --- a/kernel/sched/cpufreq_schedutil.c
> +++ b/kernel/sched/cpufreq_schedutil.c
> @@ -147,7 +147,9 @@ static unsigned int get_next_freq(struct sugov_cpu *sg_cpu, unsigned long util,
>  static void sugov_get_util(unsigned long *util, unsigned long *max)
>  {
>  	struct rq *rq = this_rq();
> -	unsigned long cfs_max = rq->cpu_capacity_orig;
> +	unsigned long cfs_max;
> +
> +	cfs_max = arch_scale_cpu_capacity(NULL, smp_processor_id());
>  
>  	*util = min(rq->cfs.avg.util_avg, cfs_max);
>  	*max = cfs_max;
> 

Thanks,
Rafael

  reply	other threads:[~2016-08-31  1:28 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-26 18:40 [PATCH 0/2] utilization changes for schedutil Steve Muckle
2016-08-26 18:40 ` [PATCH 1/2] sched: cpufreq: ignore SMT when determining max cpu capacity Steve Muckle
2016-08-31  1:27   ` Rafael J. Wysocki [this message]
2016-08-31 14:34     ` Peter Zijlstra
2016-09-12 22:25       ` Rafael J. Wysocki
2016-08-26 18:40 ` [PATCH 2/2] sched: cpufreq: use rt_avg as estimate of required RT CPU capacity Steve Muckle
2016-08-31  1:31   ` Rafael J. Wysocki
2016-08-31 14:49     ` Steve Muckle
2016-08-31 14:39   ` Peter Zijlstra
2016-08-31 15:08     ` Steve Muckle
2016-08-31 16:28       ` Thomas Gleixner
2016-08-31 16:40         ` Peter Zijlstra
2016-08-31 17:00           ` Juri Lelli
2016-09-01  7:12             ` Peter Zijlstra
2016-09-01 21:48             ` Steve Muckle
2016-09-02  9:35               ` Juri Lelli
2016-09-02 12:17                 ` Thomas Gleixner
2016-08-31 22:50           ` Rafael J. Wysocki
2016-09-02  8:12           ` Thomas Gleixner

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