From: Andrew Morton <akpm@osdl.org>
To: Dave Jones <davej@redhat.com>
Cc: davem@davemloft.net, pmarques@grupopie.com, linux-kernel@vger.kernel.org
Subject: Re: Slowdown with randomize_va_space in 2.6.12.2
Date: Wed, 6 Jul 2005 18:12:20 -0700 [thread overview]
Message-ID: <20050706181220.3978d7f6.akpm@osdl.org> (raw)
In-Reply-To: <20050706205315.GC27630@redhat.com>
Dave Jones <davej@redhat.com> wrote:
>
> On Wed, Jul 06, 2005 at 12:57:19PM -0700, David S. Miller wrote:
> > From: Paulo Marques <pmarques@grupopie.com>
> > Date: Wed, 06 Jul 2005 15:23:56 +0100
> >
> > > What is weird is that most of the extra time is being accounted as
> > > user-space time, but the user-space application is exactly the same in
> > > both runs, only the "randomize_va_space" parameter changed.
> >
> > It might be attributable to more cpu cache misses in userspace since
> > the virtual addresses of everything are changing each and every
> > invocation.
>
> On Transmeta CPUs that probably triggers a retranslation of
> x86->native bytecode, if it thinks it hasn't seen code at that
> address before.
>
ouch. What do we do? Default to off? Default to off on xmeta?
next prev parent reply other threads:[~2005-07-07 1:14 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-07-06 14:23 Paulo Marques
2005-07-06 19:57 ` David S. Miller
2005-07-06 20:53 ` Dave Jones
2005-07-06 20:58 ` David S. Miller
2005-07-07 1:12 ` Andrew Morton [this message]
2005-07-07 2:07 ` David S. Miller
2005-07-07 4:11 ` pmarques
2005-07-07 6:37 ` Arjan van de Ven
2005-07-07 6:41 ` Andrew Morton
2005-07-07 6:46 ` Arjan van de Ven
2005-07-30 0:53 ` Eric Lammerts
2005-07-30 1:20 ` Andrew Morton
2005-07-30 11:49 ` Arjan van de Ven
2005-07-30 11:55 ` Arjan van de Ven
2005-07-06 21:00 ` Arjan van de Ven
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