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    SubjectRe: [PATCH RFC/RFB] x86_64, i386: interrupt dispatch changes
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    On Mon, 2008-11-10 at 21:00 -0800, H. Peter Anvin wrote:
    > Okay, after spending most of the day trying to get something that isn't
    > completely like white noise (interesting problem, otherwise I'd have
    > given up long ago) I did, eventually, come up with something that looks
    > like it's significant. I did a set of multiple runs, and am looking for
    > the "waterfall points" in the cumulative statistics.
    >
    > http://www.zytor.com/~hpa/baseline-hpa-3000-3600.pdf
    >
    > This particular set of data points was gathered on a 64-bit kernel, so I
    > didn't try the segment technique.
    >
    > It looks to me that the collection of red lines is enough to the left of
    > the black ones that one can assume there is a significant effect,
    > probably by about a cache miss worth of time.

    This graph is a little confusing. Is the area under each curve here
    supposed to be a constant?

    Is this latency from all interrupts as seen by userspace? Or does a
    particular interrupt dominate?

    --
    Mathematics is the supreme nostalgia of our time.



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