On Wed, 2013-02-27 at 05:19 +0100, Mike Galbraith wrote: > On Tue, 2013-02-26 at 14:45 -0500, Steven Rostedt wrote: > > I would be interested in seeing what happens if we just made rt_tasks > > spin instead of sleep (call yield). Actually, if we made real-time tasks > > always spin (never sleep), just yield, if this would give us much better > > performance. > > Maybe you can get that working without the requeueing Without it being > a global head -> tail -> head thing, my big box died and died and.. As noted, prior to global queue to head, I made dead box.. a lot. However, yesterday I had to hunt down a localhost throughput regression in 3.0.65 (794ed393) anyway, and I used the opportunity to do a little concurrent tinkering... With SCHED_OTHER brain-o fixed up, as mentioned, -rt beat its NOPREEMPT parent tree at hefty tbench throughput. This morning, I tried real rt spinning again, only yielding when mandatory. With global queue to head in place, no silent box syndrome happened, worked fine. That should mean that across the box contention induced jitter can shrink by sched cost * players, no? Maybe with some refinement, experiment will work out. Longish jitter test just finished, though worst case doesn't look any better (darn), it doesn't look any worse either, so I'll poke send. (hm, maybe if I avoid pounding raw lock through the floor...) -Mike -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
