Messages in this thread | | | Date | Wed, 1 Feb 2006 14:20:54 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] Avoid moving tasks when a schedule can be made. |
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* Nick Piggin <nickpiggin@yahoo.com.au> wrote:
> >Once we've gone to the trouble of deciding which tasks to move and how > >many (and the estimate should be very conservative), and locked the source > >and destination runqueues, it is a very good idea to follow up with our > >threat of actually moving the tasks rather than bail out early. > > Oh, I forgot: Ingo once introduced some code to bail early (though for > different reasons and under different conditions), and this actually > was found to cause significant regressions in some database workloads.
well, we both did changes with that effect - pretty much any change in this area can cause a regression on _some_ workload ;) So there wont be any silver bullet.
> So it is not a nice thing to tinker with unless there is good reason.
unbound latencies with hardirqs off are obviously a good reason - but i agree that the solution is not good enough, yet.
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