Messages in this thread | | | Date | Mon, 29 Sep 2008 09:43:53 -0600 | From | "Chris Friesen" <> | Subject | Re: unpredictability in scheduler test results -- still present |
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Ingo Molnar wrote: > * Chris Friesen <cfriesen@nortel.com> wrote:
>> It turns out that disabling CONFIG_DYNAMIC_FTRACE makes the load >> balancing problem go away and causes all cpus to be used. >> >> With this option enabled, the problem seems to be present as far back >> as 2.6.27-rc2. (2.6.27-rc1 doesn't compile on my machine, and 2.6.26 >> doesn't have ftrace). >> >> I have no idea why turning on dynamic ftrace would affect load >> balancing behaviour, but it's very repeatable. The very first test >> run after booting works fine, and all successive runs fail to balance >> properly.
> OTOH, what does 'truning on dftrace' exactly mean? Just enabling it in > the .config, or also activating it via /debug/tracing/current_tracer?
Just enabling it in the .config is enough to trigger the behaviour change. I'm not explicitly activating any traces.
Chris
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