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From: Qais Yousef <qais.yousef@arm.com>
To: Peter Zijlstra <peterz@infradead.org>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>,
	Ingo Molnar <mingo@redhat.com>,
	linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Qais Yousef <qais.yousef@arm.com>
Subject: [PATCH] cpufreq: schedutil: fix equation in comment
Date: Fri,  2 Aug 2019 11:46:28 +0100	[thread overview]
Message-ID: <20190802104628.8410-1-qais.yousef@arm.com> (raw)

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;
-- 
2.17.1


             reply	other threads:[~2019-08-02 10:46 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-02 10:46 Qais Yousef [this message]
2019-08-02 13:19 ` [PATCH] cpufreq: schedutil: fix equation in comment Vincent Guittot
2019-08-05  4:54 ` Viresh Kumar
2019-08-05 13:06 ` Peter Zijlstra
2019-08-07  9:42   ` Rafael J. Wysocki
2019-08-08 11:44     ` Qais Yousef

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