From: qiwuchen55@gmail.com
To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de
Cc: linux-kernel@vger.kernel.org, chenqiwu <chenqiwu@xiaomi.com>
Subject: [PATCH] sched/pelt: use shift operation instead of division operation
Date: Mon, 24 Feb 2020 11:30:55 +0800 [thread overview]
Message-ID: <1582515055-14515-1-git-send-email-qiwuchen55@gmail.com> (raw)
From: chenqiwu <chenqiwu@xiaomi.com>
Use shift operation to calculate the periods instead of division,
since shift operation is more efficient than division operation.
Signed-off-by: chenqiwu <chenqiwu@xiaomi.com>
---
kernel/sched/pelt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c
index bd006b7..ac79f8e 100644
--- a/kernel/sched/pelt.c
+++ b/kernel/sched/pelt.c
@@ -114,7 +114,7 @@ static u32 __accumulate_pelt_segments(u64 periods, u32 d1, u32 d3)
u64 periods;
delta += sa->period_contrib;
- periods = delta / 1024; /* A period is 1024us (~1ms) */
+ periods = delta >> 10; /* A period is 1024us (~1ms) */
/*
* Step 1: decay old *_sum if we crossed period boundaries.
--
1.9.1
next reply other threads:[~2020-02-24 3:31 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-24 3:30 qiwuchen55 [this message]
2020-02-24 9:32 ` Peter Zijlstra
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