Re: [Qemu-devel] performance monitor

["Laurent Desnogues" <laurent.desnogues@gmail.com>]

On Jan 3, 2008 11:11 PM, Clemens Kolbitsch <clemens.kol@gmx.at> wrote:
>
> Well, the measuring I had in mind partly concentrats on TLB misses, page
> faults, etc. (in addition to the cycle measuring). guess i'll have to
> implement something for myself in qemu :-/

There's something not clear here:  do you want to measure your kernel
changes or do you want to profile Qemu?

As Paul clearly explained you can't do both :)

If you want to measure kernel performance oprofile is probably worth
looking at.  But you will need the real hardware.

Another option, though much more intrusive, would be to add explicit
performance counters in places you need to look at (this method can
be applied to both Qemu too).

And to say it again:  nobody can expect to measure OS performance
on a simulator, unless the simulator is directly derived from the HDL
code written by designers.  At least I would never trust such a
result ;)


Laurent