RE: Regression with SLUB on Netperf and Volanomark

[Christoph Lameter <clameter@sgi.com>]

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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