From: Waiman Long <waiman.long@hpe.com>
To: Peter Zijlstra <peterz@infradead.org>
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 22:55:02 -0500 [thread overview]
Message-ID: <565D1A16.7080105@hpe.com> (raw)
In-Reply-To: <20151130220953.GD3816@twins.programming.kicks-ass.net>
On 11/30/2015 05:09 PM, Peter Zijlstra wrote:
> 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.
I will try that out tomorrow. However, SCHED_AUTOGROUP was enabled in
the distribution kernels. So we still need to look at that with
autogroup enabled.
Cheers,
Longman
next prev parent reply other threads:[~2015-12-01 3:55 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
2015-12-01 3:55 ` Waiman Long [this message]
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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