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Message-ID: <alpine.DEB.2.00.1108131118001.32762@chino.kir.corp.google.com>
Date: Sat, 13 Aug 2011 11:28:30 -0700 (PDT)
From: David Rientjes <rientjes@...gle.com>
To: Christoph Lameter <cl@...ux.com>
cc: Pekka Enberg <penberg@...helsinki.fi>,
Andi Kleen <andi@...stfloor.org>, tj@...nel.org,
Metathronius Galabant <m.galabant@...glemail.com>,
Matt Mackall <mpm@...enic.com>,
Eric Dumazet <eric.dumazet@...il.com>,
Adrian Drzewiecki <z@...e.net>, linux-kernel@...r.kernel.org
Subject: Re: [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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