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>, Paul Turner <pjt@google.com>,
Ben Segall <bsegall@google.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Yuyang Du <yuyang.du@intel.com>
Subject: Re: [RFC PATCH 3/3] sched/fair: Use different cachelines for readers and writers of load_avg
Date: Mon, 30 Nov 2015 23:09:53 +0100 [thread overview]
Message-ID: <20151130220953.GD3816@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <565C9FDC.9020603@hpe.com>
On Mon, Nov 30, 2015 at 02:13:32PM -0500, Waiman Long wrote:
> >This begs the question tough; why are you running a global load in a
> >cgroup; and do we really need to update this for the root cgroup? It
> >seems to me we don't need calc_tg_weight() for the root cgroup, it
> >doesn't need to normalize its weight numbers.
> >
> >That is; isn't this simply a problem we should avoid?
>
> I didn't use any cgroup in my test setup. Autogroup was enabled, though.
> Booting up a 4.4-rc2 kernel caused sched_create_group() to be called 56
> times.
Yeah, can you kill autogroup and see if that helps? If not, we probably
should add some code to avoid calculating things for the root group.
next prev parent reply other threads:[~2015-11-30 22:10 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
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 [this message]
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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