Messages in this thread | | | Date | Wed, 4 Jun 2008 08:50:20 -0500 | From | Dimitri Sivanich <> | Subject | Re: [BUG] hotplug cpus on ia64 |
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On Tue, Jun 03, 2008 at 05:17:59PM -0500, Cliff Wickman wrote: > > On Fri, May 30, 2008 at 03:36:54PM +0200, Peter Zijlstra wrote: > > On Thu, 2008-05-29 at 11:32 -0500, Cliff Wickman wrote: > > > I put in counters and see that schedule() is never again entered by cpu 17 > > > after it is downed the 3rd time. > > > (it is entered after being up'd the first two times) > > > > > > The kstopmachine thread is bound to cpu 17 by __stop_machine_run()'s call > > > to kthread_bind(). > > > > > > A cpu does not schedule after being downed, of course. But it does again > > > after being up'd. > > > Why would the second up be different? Following it, if the cpu is > > > downed it never schedules again. > > > > > > If I always bind kstopmachine to cpu 0 the problem disappears. > > > > does: > > > > echo -1 > /proc/sys/kernel/sched_rt_runtime_us > > > > fix the problem? > > Yes! It does. > > Dimitri Sivanich has run into what looks like a similar problem. > Hope the above workaround is a good clue to its solution.
This fixes the problem I was seeing as well.
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