From: Jamie Lokier <jamie@shareable.org>
To: qemu-devel@nongnu.org
Cc: Anthony Liguori <aliguori@us.ibm.com>
Subject: Re: [Qemu-devel] [PATCH] Enabled building of x86_64 code on Mac OS X
Date: Tue, 27 Jan 2009 00:42:32 +0000 [thread overview]
Message-ID: <20090127004232.GE9296@shareable.org> (raw)
In-Reply-To: <200901270034.04844.paul@codesourcery.com>
Paul Brook wrote:
> > Out of curiousity, what are the benefits of using 64-bit apps in OS X?
>
> My guess is that same as most other x86 targets: The i386 legacy
> mode is crippled by lack of registers, modern x86 hardware has a big
> fat wide memory bus, and noone's bothered implementing an ILP32
> 64-bit API[1], so 64-bit apps give measurably better overall
> performance.
Except they use more memory and memory bandwidth (arguably filling
nearly half of it with zeros most of the time :-) so worse overall
performance in some cases.
-- Jamie
next prev parent reply other threads:[~2009-01-27 0:42 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-24 19:44 [Qemu-devel] [PATCH] Enabled building of x86_64 code on Mac OS X Alexander Graf
2009-01-26 15:40 ` Anthony Liguori
2009-01-27 0:34 ` Paul Brook
2009-01-27 0:42 ` Jamie Lokier [this message]
2009-01-27 0:59 ` Paul Brook
2009-01-27 1:22 ` Anthony Liguori
2009-01-27 9:21 ` Alexander Graf
2009-01-27 14:37 ` Jamie Lokier
2009-01-27 15:00 ` Laurent Desnogues
2009-01-27 0:40 ` C.W. Betts
2009-01-27 0:40 ` C.W. Betts
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