Re: [Qemu-devel] Potential to accelerate QEMU for specific architectures

[Andreas Färber]

Am 26.05.2013 07:40, schrieb Lior Vernia:
> On Sat, May 25, 2013 at 10:06 PM, Andreas Färber <address@hidden> wrote:
>> Am 24.05.2013 21:24, schrieb Lior Vernia:
>>> I am running x86 applications on an ARM device using QEMU, and found
>>> it too slow for my needs.
>>
>> Before we start going into technical details, what are you trying to
>> achieve on a high level and how did you try to do it?
>>
>> Are you using qemu-system-x86_64 or qemu-x86_64? The latest v1.5.0?
> 
> Sorry, right after I wrote the message it occured to me I should have
> mentioned that I was talking about qemu-system, either x86 or i386. At
> the moment I just ran the limbo app on a Galaxy SIII with various
> images, just to see the capabilities, and was disappointed. Limbo
> seems to run v1.1.0.

First time I hear of that app... v1.1.0 is a year old, many TCG
improvements have happened since. Suggest you contact the app's author
to get that updated to v1.5.0.

http://git.qemu.org/?p=qemu.git;a=history;f=tcg/arm;hb=HEAD

> If you suspect that it's the JNI wrapping that's causing a lot of the
> damage,

The UI (drawing) code could also be a potential bottleneck - but judging
from the files it looks as if the UI were just a Java VNC client, which
probably accesses a JNI-unaffected QEMU process?

http://code.google.com/p/limbo-android/source/browse/#git%2Fsrc

> then we can talk about compiling QEMU for ARM and running it
> natively, I just haven't been able to get that to work.

That would take some of the uncertainties out of the equation, yes.

You still haven't said what it is that you would like to do with system
emulation on your ARM device: Does it need to be x86? If you just want
access to a full Linux system from Android, you might be more interested
in investigating qemu-system-arm with KVM acceleration (requires
Cortex-A15 and 3.9+ kernel) - in practice virtualization will be faster
than anything binary translation can offer.

Andreas

-- 
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg