Messages in this thread | | | Date | Tue, 13 Mar 2007 11:57:42 +0100 | From | Andrea Arcangeli <> | Subject | Re: SMP performance degradation with sysbench |
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On Tue, Mar 13, 2007 at 09:37:54PM +1100, Nick Piggin wrote: > Well it wasn't iowait time. From Anton's analysis, I would probably > say it was time waiting for either the glibc malloc mutex or MySQL > heap mutex.
So it again makes little sense to me that this is idle time, unless some userland mutex has a usleep in the slow path which would be very wrong, in the worst case they should yield() (yield can still waste lots of cpu if two tasks in the slow paths calls it while the holder is not scheduled, but at least it wouldn't be idle time).
Idle time is suspicious for a kernel issue in the scheduler or some userland inefficiency (the latter sounds more likely). - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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