Messages in this thread | | | Subject | Re: RFC: futex_wait() can DoS the tick | From | Mike Galbraith <> | Date | Thu, 11 Jun 2015 13:41:15 +0200 |
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On Thu, 2015-06-11 at 10:34 +0200, Thomas Gleixner wrote:
> Can you try the following, please? > > Enable function tracer and hrtimer events manually. Then watch the irq > count on cpu3. If it stalls or becomes slow, then stop the trace with > > echo 0 >/sys/kernel/debug/tracing/tracing_on > > If the overhead of the function tracer hides the problem, then try just > with hrtimer, sched_switch and irq events.
Yeah, function tracer hides it. After some fiddling with buffer size to be able to ever see a tick, I finally have a trace trimmed with a tick on each end, 175ms gap between them. It's still 1.5 after xz, sending off list.
-Mike
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