On 06/23/2014 10:16 AM, Paul E. McKenney wrote: > On Mon, Jun 23, 2014 at 09:55:21AM -0700, Dave Hansen wrote: >> This still has a regression. Commit 1ed70de (from Paul's git tree), >> gets a result of 52231880. If I back up two commits to v3.16-rc1 and >> revert ac1bea85 (the original culprit) the result goes back up to 57308512. >> >> So something is still going on here. > > And commit 1ed70de is in fact the right one, so... > > The rcutree.jiffies_till_sched_qs boot/sysfs parameter controls how > long RCU waits before asking for quiescent states. The default is > currently HZ/20. Does increasing this parameter help? Easy for me to > increase the default if it does.
Making it an insane value: echo 12 > /sys/module/rcutree/parameters/jiffies_till_sched_qs average:52248706 echo 9999999 > /sys/module/rcutree/parameters/jiffies_till_sched_qs average:55712533 gets us back up _closer_ to our original 57M number, but it's still not quite there. -- 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/
