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Thread: 2.6.17.1 new perfmon code base, libpfm, pfmon available




2.6.17.1 new perfmon code base, libpfm, pfmon available
user name
2006-06-26 22:37:17
Chuck,

On Mon, Jun 26, 2006 at 01:33:03PM -0400, Chuck Ebbert
wrote:
> > Also a new version of pfmon, pfmon-3.2-060621, to
take advantage of the update in libpfm:
> > 
> >       - support for 32-bit mode AMD64 processors
> >       - updated event name parsing to prepare for
separate
> >         event unit mask management (Kevin Corry)
> >       - fix the detection of unavailable PMC
registers. it was causing crashes
> >         when used with sampling.
> > 
> > Note that I have tested 32-bit compiled
libpfm,pfmon running on an 64-bit AMD
> > perfmon kernel. I have not tested on a 32-bit AMD
linux kernel because I don't
> > have such setup. I would appreciate any feedback
on this.
> 
> 32-bit works great.  Unfortunately, pfmon is far too
limited for serious kernel
> monitoring AFAICT.  E.g. you can't select edge
counting instead of cycle
> counting.  So you can count how many clock cycles were
spent with interrupts

I put in an option to enable this mode, do pfmon --help. I
think it's called
edge-mask.

> disabled but you can't count how many times they were
disabled.  That's too bad
> because using pfmon is so easy compared to writing a
program.
> 
Try the option, and let me know if it does not work for you.

> And is someone working on kernel profiling tools that
use the perfmon2
> infrastructure on i386?  I'd like to see kernel-based
profiling that lets
> you use something like the existing 'readprofile' to
retrieve results.  This
> would be a lot better than the current timer-based
profiling.
> 
You can do this on your athlon using pfmon already, you need
to enable a
different sampling module. Here is an example:

$ pfmon --smpl-module=inst-hist -ecpu_clk_unhalted -k
--long-smpl-period=100000 \
     --resolve-addr --system-wide --session-timeout=10

This will sample (period of 100,000 cpu_clk_unhalted) in the
kernel ONLY for 10s and print  a flat
profile sorted by #samples/instruction addresses. You can
chose any event you want. Note that you can
also use this output format in per-thread mode.

Hope this helps.
-- 
-Stephane
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