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From: Abel Wu <wuyun.abel@bytedance.com>
To: Peter Zijlstra <peterz@infradead.org>,
	Mel Gorman <mgorman@suse.de>,
	Vincent Guittot <vincent.guittot@linaro.org>
Cc: Josh Don <joshdon@google.com>, Chen Yu <yu.c.chen@intel.com>,
	linux-kernel@vger.kernel.org, Abel Wu <wuyun.abel@bytedance.com>
Subject: [PATCH 4/5] sched/fair: avoid double search on same cpu
Date: Tue, 12 Jul 2022 16:20:35 +0800	[thread overview]
Message-ID: <20220712082036.5130-5-wuyun.abel@bytedance.com> (raw)
In-Reply-To: <20220712082036.5130-1-wuyun.abel@bytedance.com>

The prev cpu is checked at the beginning of SIS, and it's unlikely
to be idle before the second check in select_idle_smt(). So we'd
better focus on its SMT siblings.

Signed-off-by: Abel Wu <wuyun.abel@bytedance.com>
Reviewed-by: Josh Don <joshdon@google.com>
---
 kernel/sched/fair.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 0d7e8555bcf9..e4cf000604fc 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6344,6 +6344,8 @@ static int select_idle_smt(struct task_struct *p, int target)
 	int cpu;
 
 	for_each_cpu_and(cpu, cpu_smt_mask(target), p->cpus_ptr) {
+		if (cpu == target)
+			continue;
 		if (available_idle_cpu(cpu) || sched_idle_cpu(cpu))
 			return cpu;
 	}
-- 
2.31.1


  parent reply	other threads:[~2022-07-12  8:22 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-12  8:20 [PATCH 0/5] sched/fair: SIS improvements and cleanups Abel Wu
2022-07-12  8:20 ` [PATCH 1/5] sched/fair: ignore SIS_UTIL when has idle core Abel Wu
2022-07-13  3:47   ` Chen Yu
2022-07-13 16:14     ` Abel Wu
2022-07-14  6:19   ` Yicong Yang
2022-07-14  6:58     ` Abel Wu
2022-07-14  7:15       ` Yicong Yang
2022-07-14  8:00         ` Abel Wu
2022-07-14  8:16           ` Yicong Yang
2022-07-14  8:34             ` Yicong Yang
2022-08-04  9:59       ` Chen Yu
2022-08-15  2:54         ` Abel Wu
2022-08-10 13:50   ` Chen Yu
2022-08-15  2:44     ` Abel Wu
2022-08-29 13:08   ` Mel Gorman
2022-08-29 14:11     ` Abel Wu
2022-08-29 14:56       ` Mel Gorman
2022-09-01 13:08         ` Abel Wu
2022-09-02  4:12         ` Abel Wu
2022-09-02 10:25           ` Mel Gorman
2022-09-05 14:40             ` Abel Wu
2022-09-06  9:57               ` Mel Gorman
2022-09-07  7:27                 ` Chen Yu
2022-09-07  8:41                   ` Mel Gorman
2022-09-07  7:52                 ` Abel Wu
2022-07-12  8:20 ` [PATCH 2/5] sched/fair: default to false in test_idle_cores Abel Wu
2022-08-29 12:36   ` Mel Gorman
2022-07-12  8:20 ` [PATCH 3/5] sched/fair: remove redundant check in select_idle_smt Abel Wu
2022-08-29 12:36   ` Mel Gorman
2022-07-12  8:20 ` Abel Wu [this message]
2022-08-29 12:36   ` [PATCH 4/5] sched/fair: avoid double search on same cpu Mel Gorman
2022-07-12  8:20 ` [PATCH 5/5] sched/fair: remove useless check in select_idle_core Abel Wu
2022-08-29 12:37   ` Mel Gorman
2022-08-15 13:31 ` [PATCH 0/5] sched/fair: SIS improvements and cleanups Abel Wu

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