Messages in this thread | | | Date | Thu, 28 Aug 2008 18:33:19 +0200 | From | Andi Kleen <> | Subject | Re: [PATCH 6/6] sched: disabled rt-bandwidth by default |
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On Thu, Aug 28, 2008 at 06:25:48PM +0200, Ingo Molnar wrote: > > * Max Krasnyansky <maxk@qualcomm.com> wrote: > > > Andi Kleen wrote: > >> On Thu, Aug 28, 2008 at 01:19:13PM +0200, Peter Zijlstra wrote: > >>> On Thu, 2008-08-28 at 13:09 +0200, Andi Kleen wrote: > >>>>> Even if the system has multiple CPUs, and even if just a single CPU is > >>>>> fully utilized by an RT task, without the rt-limit the system will still > >>>>> lock up in practice due to various other factors: workqueues and tasks > >>>>> being 'stuck' on CPUs that host an RT hog. > >>>> The load balancer will not notice that a particular CPU is busy > >>>> with real time tasks? > >>> Not currently, working on that though. > >> > >> I wonder if it would make sense to break affinities in extreme case? > >> With that even the workqueues would work again. > > > > Please lets not break affinity :). > > correct, breaking affinity is a rather stupid idea.
Ok let's remove cpu hotunplug then. Probably nobody uses it anyways @)
Seriously cpu affinity on all non BP CPU is currently broken on every suspend to RAM, doing it in a few more cases when it makes the system more robust is unlikely to hurt anybody.
-Andi
-- ak@linux.intel.com
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