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Message-ID: <20230810131514.910401-1-lujialin4@huawei.com>
Date: Thu, 10 Aug 2023 13:15:14 +0000
From: Lu Jialin <lujialin4@...wei.com>
To: Ingo Molnar <mingo@...hat.com>,
Peter Zijlstra <peterz@...radead.org>,
Juri Lelli <juri.lelli@...hat.com>,
Vincent Guittot <vincent.guittot@...aro.org>,
Dietmar Eggemann <dietmar.eggemann@....com>,
Steven Rostedt <rostedt@...dmis.org>,
Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
Daniel Bristot de Oliveira <bristot@...hat.com>,
Valentin Schneider <vschneid@...hat.com>
CC: Lu Jialin <lujialin4@...wei.com>, <linux-kernel@...r.kernel.org>
Subject: [PATCH] psi: update psi irqtime when the irq delta is nozero
If update psi irqtime whether the irq delta is zero or not, the performance
will be degradation when update_rq_clock_task works frequently.
Therefore, just update psi irqtime whether the irq delta is nozero.
performace test of times(libmicro):
1) without psi_account_irqtime in update_rq_clock_task
[root@...64_perf]# ./times -E -C 200 -L -S -W -N "times" -I 200
Running: times# ./../bin-arm64/times -E -C 200 -L -S -W -N times -I 200
prc thr usecs/call samples errors cnt/samp
times 1 1 0.45210 188 0 500
2) psi_account_irqtime in update_rq_clock_task
[root@...64_perf]# ./times -E -C 200 -L -S -W -N "times" -I 200
Running: times# ./../bin-arm64/times -E -C 200 -L -S -W -N times -I 200
prc thr usecs/call samples errors cnt/samp
times 1 1 0.49408 196 0 500
3) psi_account_irqtime in update_rq_clock_task when irq delta is nozero
[root@...64_perf]# ./times -E -C 200 -L -S -W -N "times" -I 200
Running: times# ./../bin-arm64/times -E -C 200 -L -S -W -N times -I 200
prc thr usecs/call samples errors cnt/samp
times 1 1 0.45158 195 0 500
Signed-off-by: Lu Jialin <lujialin4@...wei.com>
---
kernel/sched/core.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index c52c2eba7c73..69c4f229d6d1 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -722,7 +722,8 @@ static void update_rq_clock_task(struct rq *rq, s64 delta)
rq->prev_irq_time += irq_delta;
delta -= irq_delta;
- psi_account_irqtime(rq->curr, irq_delta);
+ if (irq_delta)
+ psi_account_irqtime(rq->curr, irq_delta);
delayacct_irq(rq->curr, irq_delta);
#endif
#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
--
2.34.1
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