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SubjectRe: Slowdown with randomize_va_space in 2.6.12.2
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?
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