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From: Viresh Kumar <viresh.kumar@linaro.org>
To: Qais Yousef <qais.yousef@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Ingo Molnar <mingo@redhat.com>,
	linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] cpufreq: schedutil: fix equation in comment
Date: Mon, 5 Aug 2019 10:24:42 +0530	[thread overview]
Message-ID: <20190805045442.3pnaawo4nlrieoie@vireshk-i7> (raw)
In-Reply-To: <20190802104628.8410-1-qais.yousef@arm.com>

On 02-08-19, 11:46, Qais Yousef wrote:
> scale_irq_capacity() call in schedutil_cpu_util() does
> 
> 	util *= (max - irq)
> 	util /= max
> 
> But the comment says
> 
> 	util *= (1 - irq)
> 	util /= max
> 
> Fix the comment to match what the scaling function does.
> 
> Signed-off-by: Qais Yousef <qais.yousef@arm.com>
> ---
>  kernel/sched/cpufreq_schedutil.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> index 636ca6f88c8e..e127d89d5974 100644
> --- a/kernel/sched/cpufreq_schedutil.c
> +++ b/kernel/sched/cpufreq_schedutil.c
> @@ -259,9 +259,9 @@ unsigned long schedutil_cpu_util(int cpu, unsigned long util_cfs,
>  	 * irq metric. Because IRQ/steal time is hidden from the task clock we
>  	 * need to scale the task numbers:
>  	 *
> -	 *              1 - irq
> -	 *   U' = irq + ------- * U
> -	 *                max
> +	 *              max - irq
> +	 *   U' = irq + --------- * U
> +	 *                 max
>  	 */
>  	util = scale_irq_capacity(util, irq, max);
>  	util += irq;

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

-- 
viresh

  parent reply	other threads:[~2019-08-05  4:54 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-02 10:46 [PATCH] cpufreq: schedutil: fix equation in comment Qais Yousef
2019-08-02 13:19 ` Vincent Guittot
2019-08-05  4:54 ` Viresh Kumar [this message]
2019-08-05 13:06 ` Peter Zijlstra
2019-08-07  9:42   ` Rafael J. Wysocki
2019-08-08 11:44     ` Qais Yousef
2019-08-08 11:00 ` [tip:sched/core] " tip-bot for Qais Yousef

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