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    SubjectRe: [patch] voluntary-preempt-2.6.8.1-P0
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    On Sun, 2004-08-15 at 07:56, Ingo Molnar wrote:
    > i've uploaded the -P0 patch:
    >
    > http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-2.6.8.1-P0
    >
    > those who had APIC (and USB, under SMP) problems under previous
    > versions, are the problems still present in -P0?
    >

    The mlockall issue is still not resolved; however, I did manage to get a
    trace, which was probably not possible before because some higher
    latency but lower frequency event was overwriting /proc/latency_trace.
    So, maybe mlockall does cause xruns by having many shorter, but long
    enough to be problematic, non-preemptible sections.

    http://krustophenia.net/testresults.php?dataset=2.6.8.1-P0

    Also it seems that extract_entropy still causes high latencies, even
    though a call to preempt_schedule was added. I looked at the code in
    random.c a bit and this strikes me as an area where the algorithm could
    be improved, rather than adding a scheduling point. Do we really need
    *that* much entropy, right then? And if so, isn't there a zero-copy
    solution?

    Lee



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