> > tglx has patches that make the kthread create/destroy stuff from hotplug > > go away.. that seems like the better approach.
> Right. That cpu hotplug setup/teardown stuff is ugly. If that stuff gets removed complete that's great. The only change I'm aware of right now is the workqueue one: http://thread.gmane.org/gmane.linux.kernel/1329164 > > The main thing is avoiding the wakeup preemption from the complete() > > because we're going to sleep right after anyway. You are very likely to be preempted by the complete(), since the newly created thread has a relatively high vruntime. > > The comment doesn't really make that clear. > Right, the comment is crap. It has nothing to do with kthread_bind() > and stuff. The whole purpose is to avoid the pointless preemption > after wakeup. The only case I want to solve is the kthread_bind()->wait_task_inactive() scenario. On our platforms this patch reduces average cpu_up() time from about 9ms to 8ms, but max time goes down from 37ms to 8.5ms. cpu_up() latency becomes much more predictable. PeterB-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
