On Tue, 2012-09-11 at 11:55 -0700, Sven-Thorsten Dietrich wrote: > On Sep 11, 2012, at 11:10 AM, Mike Galbraith <efault@xxxxxx> wrote: > > > On Tue, 2012-09-11 at 17:34 +0200, Wolfgang Wallner wrote: > > > >>>> My questions are now: > >>>> > >>>> * What does this logging entry mean? > >>>> Could you please point me to some information about RT throttling > >>>> so that I can understand what's it about? > >> > >>> With stock settings, it means realtime task[s] consumed > 95% of the > >>> throttle interval (1s), so the throttle activated, allowing > >> SCHED_NORMAL > >>> tasks to have a sip of CPU, to let you try to save the box from > >> nutty RT > >>> CPU hogs. See kernel/sched_rt.c. > >> > >> I think if the application turns into a cpu hog... > > > > Where from comes 'if'? You presented evidence, so methinks there's not > > a _lot_ of room for an 'if', there's just a missing 'why'. > > Well, as you know a lot of folks do polling, but its important to make > sure not ALL cores are doing that... > [60382.945209] EplTimerHighResk: Continuous timer (handle 0x10000001) > had to skip 836 interval(s)! That and 'stops working' (as in forever) made me suspect spinner rather than transient cpu over-commit. > Need to look at the code, maybe we could add a mask to restrict > throttling per cpu (e.g. to 0) ? IMHO it's a debugging tool you turn off for normal operation. Biggest problem I've ever had with the thing is it allowing hogs to run over to the neighbors to borrow a cup of CPU. That's fixed. -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
