From: Arjan van de Ven <arjan@infradead.org>
To: Andrew Morton <akpm@osdl.org>
Cc: Dave Jones <davej@redhat.com>,
davem@davemloft.net, pmarques@grupopie.com,
linux-kernel@vger.kernel.org
Subject: Re: Slowdown with randomize_va_space in 2.6.12.2
Date: Thu, 07 Jul 2005 08:37:08 +0200 [thread overview]
Message-ID: <1120718229.3198.8.camel@laptopd505.fenrus.org> (raw)
In-Reply-To: <20050706181220.3978d7f6.akpm@osdl.org>
On Wed, 2005-07-06 at 18:12 -0700, Andrew Morton wrote:
> 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?
off-on-xmeta would be my preference; I'll cook up a patch for that.
next prev parent reply other threads:[~2005-07-07 6:37 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
2005-07-07 2:07 ` David S. Miller
2005-07-07 4:11 ` pmarques
2005-07-07 6:37 ` Arjan van de Ven [this message]
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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