On Wed, 2013-03-06 at 15:06 +0800, Michael Wang wrote: > wake_affine() stuff is trying to bind related tasks closely, but it doesn't > work well according to the test on 'perf bench sched pipe' (thanks to Peter).
so sched-pipe is a poor benchmark for this.. Ideally we'd write a new benchmark that has some actual data footprint and we'd measure the cost of tasks being apart on the various cache metrics and see what affine wakeup does for it. Before doing something like what you're proposing, I'd have a hard look at WF_SYNC, it is possible we should disable/fix select_idle_sibling for sync wakeups. The idea behind sync wakeups is that we try and detect the case where we wakeup up one task only to go to sleep ourselves and try and avoid the regular ping-pong this would otherwise create on account of the waking task still being alive and so the current cpu isn't actually idle yet but we know its going to be idle soon. -- 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/
