Messages in this thread | | | Date | Tue, 30 Sep 2008 13:12:17 +0200 | From | Ingo Molnar <> | Subject | Re: unpredictability in scheduler test results -- still present |
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* Chris Friesen <cfriesen@nortel.com> wrote:
> 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.
ok, that would be a clear ftrace bug i guess?
Ingo
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