From: Jan Kiszka <jan.kiszka@web.de>
To: "Edgar E. Iglesias" <edgar.iglesias@gmail.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] TCG slowdown
Date: Sat, 20 Aug 2011 15:37:09 -0700 [thread overview]
Message-ID: <4E503715.7080103@web.de> (raw)
In-Reply-To: <20110820205122.GA29545@zapo>
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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 <jan.kiszka@siemens.com>
> 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 <jan.kiszka@siemens.com>
> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
>
>
> 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
Jan
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next prev parent reply other threads:[~2011-08-20 22:37 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-20 20:51 [Qemu-devel] TCG slowdown Edgar E. Iglesias
2011-08-20 22:37 ` Jan Kiszka [this message]
2011-08-20 23:05 ` Edgar E. Iglesias
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