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    SubjectRe: Major regression on hackbench with SLUB (more numbers)
    On Fri, 21 Dec 2007, Ingo Molnar wrote:

    > > There are patches pending to address these issues. AFAICT Intel is
    > > testing if the regression is still there. There is no way for me to
    > > verify what is going on there and there is the constant difficulty of
    > > getting detailed information about what is going on at Intel. Every
    > > couple of month I get a result from that test. Its a really crappy
    > > situation where a lot of confusing information is passed around.
    > of course there is a way to find out, and that's why i mailed you: fix
    > the hackbench regression and i'm quite sure you'll improve the TPC-C
    > numbers as well. It shows the same kind of overhead in the profile and
    > takes just a few seconds to run. Are your pending SLUB patches in
    > 2.6.24-rc5-mm1 already?

    The tests that I wrote emulate the test behavior that was described to me
    by me.

    The fixes in 2.6.24-rc5-mm1 improved those numbers. See which I quoted earlier to you.
    However, I have no TPC-C setup here and from what I hear it takes weeks to
    run and requires a large support team for tuning.

    You can find the slab test suite for that at;a=shortlog;h=tests

    AFAICT the fixes in 2.6.25-rc5-mm1 result in double the alloc performance
    (fastpath) of SLAB.

    There are fixes that are not merged yet (the cpu alloc patchset) that
    seem to make that factor 3 because we can use the segment register to
    avoid per cpu array lookups in the fast path.

     \ /
      Last update: 2007-12-21 22:59    [W:0.020 / U:6.032 seconds]
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