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    SubjectRe: [slub p4 0/7] slub: per cpu partial lists V4
    On 8/13/11 9:28 PM, David Rientjes wrote:
    > On Tue, 9 Aug 2011, Christoph Lameter wrote:
    >
    >> The following patchset introduces per cpu partial lists which allow
    >> a performance increase of around ~10-20% with hackbench on my Sandybridge
    >> processor.
    >>
    >> These lists help to avoid per node locking overhead. Allocator latency
    >> could be further reduced by making these operations work without
    >> disabling interrupts (like the fastpath and the free slowpath) but that
    >> is another project.
    >>
    >> It is interesting to note that BSD has gone to a scheme with partial
    >> pages only per cpu (source: Adrian). Transfer of cpu ownerships is
    >> done using IPIs. Probably too much overhead for our taste. The approach
    >> here keeps the per node partial lists essentially meaning the "pages"
    >> in there have no cpu owner.
    >>
    >
    > I'm currently 35,000 feet above Chicago going about 611 mph, so what
    > better time to benchmark this patchset on my netperf testing rack!
    >
    > threads before after
    > 16 78031 74714 (-4.3%)
    > 32 118269 115810 (-2.1%)
    > 48 150787 150165 (-0.4%)
    > 64 189932 187766 (-1.1%)
    > 80 221189 223682 (+1.1%)
    > 96 239807 246222 (+2.7%)
    > 112 262135 271329 (+3.5%)
    > 128 273612 286782 (+4.8%)
    > 144 280009 293943 (+5.0%)
    > 160 285972 299798 (+4.8%)
    >
    > I'll review the patchset in detail, especially the cleanups and
    > optimizations, when my wifi isn't so sketchy.

    Andi, it'd be interesting to know your results for v4 of this patchset.
    I'm hoping to get the patches reviewed and merged to linux-next this week.

    Pekka


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