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From: Josh Don <joshdon@google.com>
To: Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
	linux-kernel@vger.kernel.org, Josh Don <joshdon@google.com>
Subject: [PATCH v2] sched/fair: ignore cache hotness for SMT migration
Date: Tue,  4 Aug 2020 12:34:13 -0700	[thread overview]
Message-ID: <20200804193413.510651-1-joshdon@google.com> (raw)
In-Reply-To: <20200804105619.GE2657@hirez.programming.kicks-ass.net>

SMT siblings share caches, so cache hotness should be irrelevant for
cross-sibling migration.

Proposed-by: Venkatesh Pallipadi <venki@google.com>
Signed-off-by: Josh Don <joshdon@google.com>
---
 kernel/sched/fair.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 1a68a0536add..abdb54e2339f 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7402,6 +7402,10 @@ static int task_hot(struct task_struct *p, struct lb_env *env)
 	if (unlikely(task_has_idle_policy(p)))
 		return 0;
 
+	/* SMT siblings share cache */
+	if (env->sd->flags & SD_SHARE_CPUCAPACITY)
+		return 0;
+
 	/*
 	 * Buddy candidates are cache hot:
 	 */
-- 
2.28.0.163.g6104cc2f0b6-goog


  parent reply	other threads:[~2020-08-04 19:34 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-04  0:06 [PATCH] sched/fair: ignore cache hotness for SMT migration Josh Don
2020-08-04 10:56 ` peterz
2020-08-04 19:24   ` Josh Don
2020-08-04 19:34   ` Josh Don [this message]
2020-08-10  6:14     ` [PATCH v2] " Srikar Dronamraju
2020-08-10  8:55       ` Valentin Schneider
2020-08-27  7:54     ` [tip: sched/core] sched/fair: Ignore " tip-bot2 for Josh Don

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