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    SubjectRe: [patch] voluntary-preempt-2.6.8.1-P0
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    On Sun, 2004-08-15 at 22:43, Ingo Molnar wrote:
    > * Lee Revell <rlrevell@joe-job.com> wrote:
    >
    > > http://krustophenia.net/testresults.php?dataset=2.6.8.1-P0
    >
    > nice. (What is the difference between the left-hand and the right-hand
    > graphs - why is the right-hand side one 'wider'?)
    >

    The right hand graph is logarithmically scaled on the y axis (set
    logscale y in gnuplot). Some of the latencies are rare enough to not
    show up at all on the linear scale, like the peak in the 400s.

    > > The peaks on this graph should correspond directly to the length of
    > > the non-preemptible critical section reported by Ingo's latency
    > > tracer. I think the large peak around 580-600usecs is caused by the
    > > extract_entropy issue (which can be hit by regular processes and
    > > ksoftirqd), and the large peak around 80-100 by the XFree86 unmap_vmas
    > > issue, as the times match and these are by far the most common
    > > reported in latency_trace.
    >
    > just to check this theory, could you make __check_and_rekey() an empty
    > function? This should still produce a working random driver, albeit at
    > much reduced entropy. If these latencies have a relationship to the
    > mlockall() issue then this change should have an effect.
    >

    Sure, will try this next.

    Lee

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