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Date: Fri, 19 Aug 2011 04:13:37 +0100
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From: Peter Maydell <peter.maydell@linaro.org>
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Subject: Re: [Qemu-devel] Multi-threaded user program support?
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To: =?UTF-8?B?6Zmz6Z+L5Lu7?= <chenwj@iis.sinica.edu.tw>
Cc: qemu-devel@nongnu.org

On 19 August 2011 03:59, =E9=99=B3=E9=9F=8B=E4=BB=BB <chenwj@iis.sinica.edu=
.tw> wrote:
>> More generally and not x86-specific, there are problems with
>> the multithreaded user-mode support which I suspect exist because
>> nobody has ever sat down and worked out a coherent design for it,
>> including what might need to be thread-local and what locking
>> is required. So the result is that it mostly works but if you
>
> =C2=A0You mean some QEMU data structures need to be thread-local or lock
> protected in order to emulate guest multi-threaded program correctly?

Approximately, yes (the third option being "redesign the data
structure so it can be sensibly protected"). See
https://bugs.launchpad.net/qemu/+bug/668799 for discussion of
one example.

None of this is impossibly difficult; it just requires that somebody
sits down and actually works through the problems and fixes them.

-- PMM