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Date: Sat, 25 Jun 2011 18:28:08 +0200
From: "felix.matenaar@rwth-aachen" <felix.matenaar@rwth-aachen.de>
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Subject: Re: [Qemu-devel] QEMU timing requirements
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To: qemu-devel@nongnu.org

On 06/25/2011 06:26 AM, Mulyadi Santosa wrote:
> On Sat, Jun 25, 2011 at 09:34, felix.matenaar@rwth-aachen
> <felix.matenaar@rwth-aachen.de>  wrote:
>> Hello,
>>
>> I am currently implementing some heuristics using a patched qemu
>> (i386-softmmu). Two of them take some time for each vm memory access. If I
>> run them both, suddenly qemu segfaults while executing a BBL. Using just one
>> of them never triggers this problem.
> "Two" instances of Qemu running at the same time, you mean?
>

No. What I do is using gen_helper_ to compile hooks into call/ret/jmp 
and memory access. The Heuristics can then hook the events so 
calculation is done during the execution of a basic block. I thought 
that it could be possible that Qemu sets a timeout for BBL execution to 
prevent CPU monopolization by e.g. a long sequence of rep. That would 
make sense because my heuristics calculation time falls into the BBL 
execution time for Qemu. Does anyone know more about that?

Regards,
     Felix