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Date: Sun, 19 Oct 2003 08:43:27 -0700
From: "Martin J. Bligh" <mbligh@aracnet.com>
To: Andrew Morton <akpm@osdl.org>, Adrian Bunk <bunk@fs.tum.de>
cc: linux-kernel@vger.kernel.org
Subject: Re: [2.6 patch] add a config option for -Os compilation
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>> On Sat, Oct 18, 2003 at 10:24:02AM -0700, Andrew Morton wrote:
>> > "Martin J. Bligh" <mbligh@aracnet.com> wrote:
>> > > 
>> > > Please don't - I benchmarked it a while ago, and it's definitely slower.
>> > 
>> > Alan said he generally found -Os to be faster...
>> 
>> Not exactly:
>>   http://www.ussg.iu.edu/hypermail/linux/kernel/0211.0/1513.html
>> 
> 
> http://www.ussg.iu.edu/hypermail/linux/kernel/0308.1/1261.html
> 
> And bear in mind that you can see significant changes in benchmark results
> between equivalent kernels even when the optimisation level is kept the
> same, due to aliasing and alignment luck.
> 
> It would take a quite a lot of work to measure this properly.  A simple A/B
> comparison doesn't cut it.

So why are we changing it then? ;-) We don't seem to have much evidence
either way. What are the distros doing?

M.