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Date: Fri, 19 Jun 2009 08:46:56 +0200
Message-ID: <761ea48b0906182346u5d05c1dev323acd98432638@mail.gmail.com>
Subject: Re: [Qemu-devel] POLL: Support for instrumentation?
From: Laurent Desnogues <laurent.desnogues@gmail.com>
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To: Sami Kiminki <sami.kiminki@tkk.fi>
Cc: qemu-devel@nongnu.org

On Thu, Jun 18, 2009 at 4:54 PM, Sami Kiminki<sami.kiminki@tkk.fi> wrote:
>
> We are considering doing some work on instrumentation support for QEMU.
> But before rushing into implementation, I wonder if there is more
> general interest in this subject, and if so, what kind of
> instrumentation would you like to see?

I am definitely interested. But again, being the less intrusive
possible is a must from my point of view. Not degrading
performance too much is also a must.

Things I'd like to see:

- instruction traces (including category mix)
- memory traces
- canceled conditional instructions
- taken/non taken branches
- flexible branch prediction
- flexible multi-level cache simulation

Some of these things can be done after execution, provided
enough information is collected at runtime.  By flexible, I mean
an easy to change for instance predictor(s) and cache
geometry.

This is a huge subject with a huge literature :-)

>>From an implementation point of view, doing it so that it is
easy to add runtime info collection and post execution
info extraction will be difficult, especially if you want it to
be accepted into mainline.


Laurent