Re: [Qemu-devel] Re: Performance Monitoring

["Cheif Jones" <avivgnet@gmail.com>]

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Hi All,

Thanks for all the good advice!

I do not have the HW and so I need an emulator. Also the target arch is not
x86, it has to be some RISC (ARM, PPC).

I would like to run an OS, say Linux, and take a sample for a small period
of time (seconds) while some app(s) are running and get a list of opcode
names and how many times they were executed. I'm not interested in CPI at
the moment.

Vince, I briefly read your paper and went through the patch . It is very
interesting and maybe i can use it for what i need. Questions:

   - Is there a 1-1 correspondence between a BBV and a target CPU opcode?
   - If i use the QEMU to generate BBVs, and the other tools you mentioned
   that gets BBV as input, will i be able to see the opcode name (and not just
   a uniqe ID that goes with BBV)
   - Paul mentioned "With either alternative you'll still have issues with
   exceptions. MMU faults abort a TB early, so will screw up your statistics.
   One possibility is to terminate a TB on every memory access, like we do for
   watchpoints." - is this an issue addressed by your patch?

Thanks,
Chief

   -

   -


On 5/22/08, Glauber
>
>
> >> is compiled JIT and runs natively).
> >
> > Is an actual emulator necessary, or could you use something like an
> > instrumented UML kernel? I'd think that would be a much simpler approach.
>
>
> Since he claims to need opcode statistics, and UML won't trap any
> instruction but the privileged ones, does not seem feasible.
>
>
> --
> Glauber Costa.
> "Free as in Freedom"
> http://glommer.net
>
> "The less confident you are, the more serious you have to act."
>
>
>

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