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Date: Thu, 1 Dec 2011 17:30:14 +0800
From: =?utf-8?B?6Zmz6Z+L5Lu7?= <chenwj@iis.sinica.edu.tw>
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Subject: Re: [Qemu-devel] Improve QEMU performance with LLVM codegen and
 other techniques
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To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Alexander Graf <agraf@suse.de>, =?utf-8?B?6Zmz6Z+L5Lu7?= <chenwj@iis.sinica.edu.tw>, qemu-devel@nongnu.org

Hi, Stefan

> It would be interesting to use an optimized interpreter instead of TCG,
> then go to LLVM for hot traces.  This is more HotSpot-like with the ide=
a
> being that the interpreter runs through initialization and rarely
> executed code without a translation overhead.  For the hot paths LLVM
> kicks in and high-quality translated code is executed.

  Not sure if it's doable. I can only tell you we rely on QEMU frontend t=
o
disassemble guest binary into TCG IR, then translate TCG IR into LLVM IR.
And talk about the translation overhead, the time QEMU frontend spend is
negligible.

Regards,
chenwj

--=20
Wei-Ren Chen (=E9=99=B3=E9=9F=8B=E4=BB=BB)
Computer Systems Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667
Homepage: http://people.cs.nctu.edu.tw/~chenwj