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Message-ID: <Pine.LNX.4.64.0705072150490.4939@schroedinger.engr.sgi.com>
Date: Mon, 7 May 2007 21:57:32 -0700 (PDT)
From: Christoph Lameter <clameter@....com>
To: Tim Chen <tim.c.chen@...ux.intel.com>
cc: "Chen, Tim C" <tim.c.chen@...el.com>,
"Siddha, Suresh B" <suresh.b.siddha@...el.com>,
"Zhang, Yanmin" <yanmin.zhang@...el.com>,
"Wang, Peter Xihong" <peter.xihong.wang@...el.com>,
Arjan van de Ven <arjan@...radead.org>,
linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: RE: Regression with SLUB on Netperf and Volanomark
On Mon, 7 May 2007, Tim Chen wrote:
> However, the output from TCP_STREAM is quite stable.
> I am still seeing a 4% difference between the SLAB and SLUB kernel.
> Looking at the L2 cache miss rate with emon, I saw 6% more cache miss on
> the client side with SLUB. The server side has the same amount of cache
> miss. This is test under SMP mode with client and server bound to
> different core on separate package.
If this is cache miss related then a larger page order may take are
of this. Boot with (assume you got 2.6.21-mm1 at least...)
slub_min_order=6 slub_max_order=7
which will give you an allocation unit of 256k. Just tried it. It
actually works but has no effect here whatsoever on UP netperf
performance. netperf performance dropped from 6MB(slab)/6.2MB(slub) on
2.6.21-rc7-mm1 to 4.5MB (both) on 2.6.21-mm1. So I guess there is
something also going on with the networking layer.
Still have not found a machine here where I could repeat your
results.
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