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

[Lior Vernia]

On Sun, May 26, 2013 at 12:00 PM, Andreas Färber <address@hidden> wrote:
> 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?

Yes, that was my impression as well.

>
> 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.

A little off-topic, so maybe I'll start a different thread on how I
tried to compile and what I got when trying to run it.

>
> 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.

Yes, I'm sorry if I haven't made that clear enough, the mission
statement would be to run an arbitrary x86 system image on an ARM
host. Preferably as a non-privileged user. Both of which led me to
QEMU.

Lior.

>
> Andreas
>
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