Messages in this thread | | | Date | Tue, 8 Apr 2008 15:54:00 +0200 | From | Ingo Molnar <> | Subject | Re: [rc8] Regression: key repeats and skips in music during compilation |
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* Frans Pop <elendil@planet.nl> wrote:
> > and a more laborous way would be to trace such skipping: > > http://people.redhat.com/mingo/sched-devel.git/howto-trace-latencies.txt > > Tried this too, but the problem is that the skips don't happen while > tracing is enabled. Apparently the system overhead is so high that it > changes the scheduling behavior. Attached one trace that was made > immediately after a skip happened. Maybe it helps.
one way to reduce tracing overhead would be:
echo nostacktrace > /sys/kernel/debug/tracing/iter_ctrl echo nosched-tree > /sys/kernel/debug/tracing/iter_ctrl
and making sure you only have CONFIG_CONTEXT_SWITCH_TRACER=y enabled, not any of the other tracers.
but ... if there's a narrow wakeup race, even lightweight tracing could make it go away.
Ingo
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