Messages in this thread | | | Date | Tue, 1 Dec 2015 09:49:44 +0100 | From | Peter Zijlstra <> | Subject | Re: [RFC PATCH 3/3] sched/fair: Use different cachelines for readers and writers of load_avg |
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On Mon, Nov 30, 2015 at 10:55:02PM -0500, Waiman Long wrote: > 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.
Meh, or just tell the people that have stupid large machines to use noautogroup on boot (its of questionable benefit in the first place imo, esp. on servers).
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