On Tue, 2008-02-12 at 10:23 +0100, Mike Galbraith wrote: > If you plunk a usleep(1) in prior to calling thread_func() does your > testcase performance change radically? If so, I wonder if the real > application has the same kind of dependency.
The answer is yes for 2.6.22, and no for 2.6.24, which surprised me. 2.6.22.17-smp homer:..local/tmp # ./threadtest2 10000000 loops time 16215 ms 10000000 loops time 16268 ms 10000000 loops time 16246 ms homer:..local/tmp # ./threadtest3 (with usleep(1)) 10000000 loops time 13938 ms 10000000 loops time 13921 ms 10000000 loops time 13898 ms 2.6.24.1-smp homer:..local/tmp # ./threadtest2 10000000 loops time 14663 ms 10000000 loops time 14523 ms 10000000 loops time 14466 ms homer:..local/tmp # ./threadtest3 10000000 loops time 14513 ms 10000000 loops time 14500 ms 10000000 loops time 14464 ms echo 0 > /proc/sys/kernel/sched_child_runs_first homer:..local/tmp # ./threadtest2 10000000 loops time 14157 ms 10000000 loops time 14097 ms 10000000 loops time 14153 ms homer:..local/tmp # ./threadtest3 10000000 loops time 14065 ms 10000000 loops time 14075 ms 10000000 loops time 14018 ms -- 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/
