Date: Thu, 15 Apr 2010 15:53:09 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Taras Glek <tglek@mozilla.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Downsides to madvise/fadvise(willneed) for application startup
Message-Id: <20100415155309.2649a29b.akpm@linux-foundation.org>
In-Reply-To: <4BBA6776.5060804@mozilla.com>
References: <4BBA6776.5060804@mozilla.com>
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On Mon, 05 Apr 2010 15:43:02 -0700
Taras Glek <tglek@mozilla.com> wrote:

> To make matters worse, 
> the compile-time linker + gcc lay out code in a manner that does not 
> correspond to how the resulting executable will be executed(ie the 
> layout is basically random).

Yes, the linker scrambles the executable's block ordering.

This just isn't an interesting case.  World-wide, the number of people
who compile their own web browser and execute it from the file which ld
produced is, umm, seven.

So I'd suggest that you always copy the executable to a temp file and
mv it back before running any timing tests.

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