linux-kernel - Re: Downsides to madvise/fadvise(willneed) for application startup

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20100415155309.2649a29b.akpm@linux-foundation.org>
Date:	Thu, 15 Apr 2010 15:53:09 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Taras Glek <tglek@...illa.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: Downsides to madvise/fadvise(willneed) for application startup

On Mon, 05 Apr 2010 15:43:02 -0700
Taras Glek <tglek@...illa.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.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/