On Fri, 2014-05-02 at 07:32 +0200, Mike Galbraith wrote: > On Fri, 2014-05-02 at 00:42 -0400, Rik van Riel wrote: > > Currently sync wakeups from the wake_affine code cannot work as > > designed, because the task doing the sync wakeup from the target > > cpu will block its wakee from selecting that cpu. > > > > This is despite the fact that whether or not the wakeup is sync > > determines whether or not we want to do an affine wakeup... > > If the sync hint really did mean we ARE going to schedule RSN, waking > local would be a good thing. It is all too often a big fat lie.
BTW, we used to have avg_overlap and a sync less heuristic to improve the accuracy of the sync wakeup hint, but I ripped it out because it was dead wrong far too often. You can try reviving it, but preemption among other things break it. You'll have better luck with a simple context switch rate heuristic, but that's less than perfect too. -Mike -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
