Messages in this thread | | | Date | Thu, 10 Jan 2008 09:43:46 -0500 (EST) | From | Steven Rostedt <> | Subject | Re: [PATCH] Kick CPUS that might be sleeping in cpus_idle_wait |
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On Thu, 10 Jan 2008, Ingo Molnar wrote: > > FYI, I just hit this hang on 2.6.24-rc6 without any extra patches. So, > > unless 2.6.24-rc7 did anything to fix this issue, this is a high > > priority bug (IMHO). > > i'm wondering why this only triggered now. Is this something new in > 2.6.24?
It only triggeres with the switching of the idle governors. And not just one, you need to switch twice. The first loading of a governor does not call cpu_idle_wait, but the second one does. NO_HZ must also be enabled, plus this needs to happen when no events or threads are scheduled to run on a CPU, which limits this to boot up.
Also, this only seems to happen on my 2x2 (4way) and only once in a while.
I'm surprised that I'm the only one so far to report it. I can boot up the 2.6.23 kernel on this box to see if it also hangs sometimes. But, as I said, it may take several hundreds of tries to see it.
-- Steve
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