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SubjectRe: [slub p4 0/7] slub: per cpu partial lists V4
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.


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