Messages in this thread | | | Subject | Re: [PATCH 5/5] sched,futex: Provide delayed wakeup list | From | Davidlohr Bueso <> | Date | Sat, 23 Nov 2013 21:25:40 -0800 |
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On Sat, 2013-11-23 at 13:01 +0100, Peter Zijlstra wrote: > > I used to have a patch to schedule() that would always immediately fall > > through and only actually block on the second call; it illustrated the > > problem really well, in fact so well the kernels fails to boot most > > times. > > I found the below on my filesystem -- making it apply shouldn't be hard. > Making it work is the same effort as that patch you sent, we need to > guarantee all schedule() callers can deal with not actually sleeping -- > aka. spurious wakeups.
Thanks, I'll definitely try the patch and see what comes up.
> > I don't think anybody ever got that thing to run reliable enough to see > if the idea proposed in the patch made any difference to actual > workloads though.
Since your idea can also be applied to sysv sems (patch 3/3 back then), I can definitely do some Oracle runs which IIRC, also likes doing multiple wakeups at once. In any case this patch deals very nicely with our customer workload, which is why I believe its particularly good here.
Thanks, Davidlohr
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