On Thu, 2013-03-07 at 09:36 +0100, Peter Zijlstra wrote: > 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.
If nobody beats me to it, I'm going to try tracking shortest round trip to idle, and use a multiple of that to shut select_idle_sibling() down. If avg_idle approaches round trip time, there's no win to be had, we're just wasting cycles. -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/
