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Re: [Qemu-devel] TCG slowdown
From: |
Edgar E. Iglesias |
Subject: |
Re: [Qemu-devel] TCG slowdown |
Date: |
Sun, 21 Aug 2011 01:05:44 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Sat, Aug 20, 2011 at 03:37:09PM -0700, Jan Kiszka wrote:
> On 2011-08-20 13:51, Edgar E. Iglesias wrote:
> > Lately, my TCG emulated machines have been running terribly slow.
> > Like a factor 3 or 4 slower, hardly usable.
> >
> > I bisected it to this:
> >
> > commit d5ab9713d2d4037fd56b0adddd26c8d4dc11cf09
> > Author: Jan Kiszka <address@hidden>
> > Date: Tue Aug 2 16:10:21 2011 +0200
> >
> > Avoid allocating TCG resources in non-TCG mode
> >
> > Do not allocate TCG-only resources like the translation buffer when
> > running over KVM or XEN. Saves a "few" bytes in the qemu address space
> > and is also conceptually cleaner.
> >
> > Signed-off-by: Jan Kiszka <address@hidden>
> > Signed-off-by: Anthony Liguori <address@hidden>
> >
> >
> > It turns out that the init of the tb cache is now moved to before ram_size
> > gets it's default value. And because the default tb cache size, if no
> > -tb-size option is given, is based on the ram_size it is now zero..
>
> Yes, already stumbled over that regression myself. See
> http://thread.gmane.org/gmane.comp.emulators.qemu/113547
OK, thanks. I've pushed your fix.
Cheers