From: Aurelien Jarno <aurelien@aurel32.net>
To: Richard Henderson <rth@twiddle.net>
Cc: Blue Swirl <blauwirbel@gmail.com>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] target-sparc register window handling
Date: Tue, 9 Oct 2012 19:06:59 +0200 [thread overview]
Message-ID: <20121009170659.GE9643@ohm.aurel32.net> (raw)
In-Reply-To: <5074568C.20602@twiddle.net>
On Tue, Oct 09, 2012 at 09:53:32AM -0700, Richard Henderson wrote:
> On 10/07/2012 11:17 PM, Aurelien Jarno wrote:
> > For what it worth, I measure a 4% slow down booting a sparc64 guest on a
> > Core-i5 2500 machine. I guess the memcpy() of the register windows is
> > more expensive that the gain on the TCG side, though it should be
> > probably be confirmed using some profiling tools.
>
> Confirmed with userland testing (running cc1plus on large input),
> and I see much more than 4% slow down -- more like 15%. I can reduce
Not surprising. System mode spends a lot of time outside of the TCG
code, and when doing TCG code, it spends most of its time in the
qemu_ld/st code. User mode has a very simple qemu_ld/st code.
--
Aurelien Jarno GPG: 1024D/F1BCDB73
aurelien@aurel32.net http://www.aurel32.net
prev parent reply other threads:[~2012-10-09 17:07 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-06 0:00 [Qemu-devel] [PATCH] target-sparc register window handling Richard Henderson
2012-10-06 0:00 ` [Qemu-devel] [PATCH] target-sparc: Use TCG registers for windowed registers Richard Henderson
2012-10-06 10:15 ` [Qemu-devel] [PATCH] target-sparc register window handling Aurelien Jarno
2012-10-08 6:17 ` Aurelien Jarno
2012-10-09 16:53 ` Richard Henderson
2012-10-09 17:06 ` Aurelien Jarno [this message]
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