Re: [Qemu-devel] [PATCH] target-sparc register window handling

[Aurelien Jarno]

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
address@hidden                 http://www.aurel32.net