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    SubjectRe: [PATCH] kallsyms data size reduction / lookup speedup
    viro@parcelfarce.linux.theplanet.co.uk wrote:
    > On Wed, Aug 25, 2004 at 08:09:33PM +0100, Paulo Marques wrote:
    >
    >>Matt Mackall wrote:
    >>
    >>>...
    >>>
    >>>FYI, killing the seq_file stuff will likely prove unpopular. So you'll
    >>>want to do that in a separate patch. If it doesn't affect the way
    >>>you're handling compression, please repost your compression patch. I
    >>>have a few comments, but otherwise I think we should move forward with it.
    >>
    >>I'm still not sure that the seq_file is the culprit, but doing
    >>a 10000 symbol decompression in a user space application takes
    >>about 340us, whereas doing a "time cat /proc/kallsyms > /dev/null"
    >>gives approx. 0.2s! (this is all on a Pentium4 2.8GHz)
    >>
    >>*If* the seq_file is the culprit, then I don't think removing
    >>it (or improving it) will be unpopular.
    >
    >
    > If it really spends that much in seq_file, I bet anything that it got
    > *very* dumb iterator. Which should be fixable...

    That is why I kept a big *If* in that sentence. I'm quite new to all
    this, and I'm still reading a lot of source code.

    If the culprit is in fact seq_file, and seq_file can be improved in a
    way that works for everyone (not only kallsyms), then I also agree
    that is is the way to go. But hunting this down might prove that the
    problem is somewhere else. It is just too soon to draw conclusions.

    --
    Paulo Marques - www.grupopie.com
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