From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Josh Don <joshdon@google.com>
Cc: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
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
Subject: Re: [PATCH v2] sched/fair: ignore cache hotness for SMT migration
Date: Mon, 10 Aug 2020 11:44:06 +0530 [thread overview]
Message-ID: <20200810061406.GA15559@linux.vnet.ibm.com> (raw)
In-Reply-To: <20200804193413.510651-1-joshdon@google.com>
* Josh Don <joshdon@google.com> [2020-08-04 12:34:13]:
> 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;
> +
If this for retaining cache hotness, should we look at
SD_SHARE_PKG_RESOURCES instead of SD_SHARE_CPUCAPACITY?
> /*
> * Buddy candidates are cache hot:
> */
> --
> 2.28.0.163.g6104cc2f0b6-goog
>
--
Thanks and Regards
Srikar Dronamraju
next prev parent reply other threads:[~2020-08-10 6:14 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 ` [PATCH v2] " Josh Don
2020-08-10 6:14 ` Srikar Dronamraju [this message]
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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