From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <Waiman.Long@hpe.com>
Cc: Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org,
Scott J Norton <scott.norton@hpe.com>,
Douglas Hatch <doug.hatch@hpe.com>
Subject: Re: [PATCH 2/3] sched/fair: Move hot load_avg into its own cacheline
Date: Mon, 30 Nov 2015 11:23:22 +0100 [thread overview]
Message-ID: <20151130102322.GI17308@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1448478580-26467-3-git-send-email-Waiman.Long@hpe.com>
On Wed, Nov 25, 2015 at 02:09:39PM -0500, Waiman Long wrote:
> +++ b/kernel/sched/sched.h
> @@ -248,7 +248,12 @@ struct task_group {
> unsigned long shares;
>
> #ifdef CONFIG_SMP
> - atomic_long_t load_avg;
> + /*
> + * load_avg can be heavily contended at clock tick time, so put
> + * it in its own cacheline separated from the fields above which
> + * will also be accessed at each tick.
> + */
> + atomic_long_t load_avg ____cacheline_aligned;
Same as with the other patch; this only works if the structure itself is
cacheline aligned, which I don't think it is.
> #endif
> #endif
>
> --
> 1.7.1
>
next prev parent reply other threads:[~2015-11-30 10:23 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-25 19:09 [PATCH 0/3] sched/fair: Reduce contention on tg's load_avg Waiman Long
2015-11-25 19:09 ` [PATCH 1/3] sched/fair: Avoid redundant idle_cpu() call in update_sg_lb_stats() Waiman Long
2015-12-04 11:57 ` [tip:sched/core] " tip-bot for Waiman Long
2015-11-25 19:09 ` [PATCH 2/3] sched/fair: Move hot load_avg into its own cacheline Waiman Long
2015-11-30 10:23 ` Peter Zijlstra [this message]
2015-11-25 19:09 ` [RFC PATCH 3/3] sched/fair: Use different cachelines for readers and writers of load_avg Waiman Long
2015-11-30 10:22 ` Peter Zijlstra
2015-11-30 19:13 ` Waiman Long
2015-11-30 22:09 ` Peter Zijlstra
2015-12-01 3:55 ` Waiman Long
2015-12-01 8:49 ` Peter Zijlstra
2015-12-01 10:44 ` Mike Galbraith
2015-12-02 18:48 ` Waiman Long
2015-11-30 22:29 ` Peter Zijlstra
2015-12-01 4:00 ` Waiman Long
2015-12-01 8:47 ` Peter Zijlstra
2015-12-02 18:44 ` Waiman Long
2015-11-30 22:32 ` Peter Zijlstra
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