On Mon, 2008-02-11 at 11:26 -0600, Olof Johansson wrote: > On Mon, Feb 11, 2008 at 09:15:55AM +0100, Mike Galbraith wrote: > > Piddling around with your testcase, it still looks to me like things > > improved considerably in latest greatest git. Hopefully that means > > happiness is in the pipe for the real workload... synthetic load is > > definitely happier here as burst is shortened. > > The real workload doesn't see much of an improvement. The changes I did > when tinkering yesterday seem like they're better at modelling just > what's going on with that one.
So the real application is trying to yield? If so, you could try prodding /proc/sys/kernel/sched_compat_yield. It shouldn't matter if you yield or not really, that should reduce the number of non-work spin cycles wasted awaiting preemption as threads execute in series (the problem), and should improve your performance numbers, but not beyond single threaded. If I plugged a yield into the busy wait, I would expect to see a large behavioral difference due to yield implementation changes, but that would only be a symptom in this case, no? Yield should be a noop. -Mike -- 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/