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Date: Mon, 17 Mar 2008 20:27:14 +0100
From: Jens Axboe <jens.axboe@oracle.com>
To: "Alan D. Brunelle" <Alan.Brunelle@hp.com>
Cc: linux-kernel@vger.kernel.org, npiggin@suse.de, dgc@sgi.com
Subject: Re: [PATCH (block.git) 0/2] IO CPU affinity update:
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On Mon, Mar 17 2008, Alan D. Brunelle wrote:
> Hi Jens -
> 
> Two patches: 
> 
> 1. Adds in the IRQ saving to generic_smp_call_function_single_interrupt (as you had suggested).
> 2. Ensures a single IPI generated to get a remote function call handler going. 
> 
> So far it is working better than before on the 4-way IA64 w/ the mkfs/untar/make test suite - after 22 runs:
> 
> Part  RQ   MIN     AVG     MAX      Dev
> ----- --  ------  ------  ------  ------
>  mkfs  0  18.786  19.253  19.655   0.241
>  mkfs  1  18.639  19.182  19.786   0.293
> 
> untar  0  17.140  17.486  18.250   0.322
> untar  1  16.951  17.494  18.274   0.350
> 
>  make  0  22.927  24.310  34.339   2.287
>  make  1  22.863  23.788  24.189   0.333
> 
>  comb  0  59.478  61.049  70.320   2.142
>  comb  1  59.875  60.463  61.305   0.458
> 
>  psys  0   3.96%   4.14%   4.39%   0.100
>  psys  1   3.60%   3.85%   4.19%   0.176
> 
> So we're seeing reduced time (~1.0%) and reduced %sys to do it (7.0%).
> The tighter deviations for make with rq=1 may be interesting... :-)
> 
> I've compiled & booted the patches for x86_64 - rq=1 is working on
> that platform too.

This is starting to look pretty good! Thanks a lot for these results,
and the ->activated optimizations. I had a feeling the unstable results
were something like this, missing ipi's.

-- 
Jens Axboe