Messages in this thread | | | Subject | Re: perf_events: proposed fix for broken intr throttling (repost) | From | Peter Zijlstra <> | Date | Wed, 04 Jan 2012 23:49:56 +0100 |
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On Wed, 2012-01-04 at 21:33 +0000, Stephane Eranian wrote: > > I don't think it needs that, I do dislike the unconditional iterate all > > events thing though. Maybe we can set some per-cpu state indicating > > someone got throttled (rare under normal operation -- you'd hope) and > > only iterate to unthrottle when we find this set. > > > Could try that too. > > > I think the event scheduling resulting from migration will already > > re-enable the event, avoiding the loss of unthrottle due to that.. > > although it would be good to verify that. > > > Yes, you're not dead forever, but still it is not acceptable as is.
Oh for sure, I didn't mean it like that. What I was getting at is a counter getting throttled on one cpu, setting the per-cpu variable, getting migrated and not getting unthrottled due to now living on another cpu which doesn't have the per-cpu thing set.
If the scheduling resulting from the migration already unthrottles that scenario can't happen.
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