Messages in this thread | | | From | Paul Turner <> | Date | Tue, 19 Jun 2012 01:45:05 -0700 | Subject | Re: [RFC][PATCH 4/4] sched/fair: Optimize cgroup pick_next_task_fair |
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On Fri, Jun 15, 2012 at 7:03 AM, Peter Zijlstra <peterz@infradead.org> wrote: > On Thu, 2012-06-14 at 23:19 +0200, Peter Zijlstra wrote: >> On Thu, 2012-06-14 at 15:29 +0200, Peter Zijlstra wrote: >> > Since commit 2f36825b1 ("sched: Next buddy hint on sleep and preempt >> > path") it is likely we pick a new task from the same cgroup, doing a put >> > and then set on all intermediate entities is a waste of time, so try to >> > avoid this. >> >> I just noticed put_prev_entity() also does the bandwidth enforcement >> stuff, I think I just broke that. Will have a peek at fixing that >> tomorrow or so. > > Damn, that's annoying, that wants to be done bottom-up, while we're now > doing a top-down selection. pjt any sane ideas?
I'll have a look at this tomorrow, but I think this is fairly immediately resolvable -- I don't see any immediate reason we need to do full enforcement here. The only interesting thing we really need to do in the put_path is the voluntary return of quota, which -- if we need to do it -- we will get to do since that occurs iff the entity is no longe runnable and actually getting a put().
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