performance counters was Re: (no subject)

[Harald Servat]

On Fri, Jan 16, 2009 at 3:47 AM, Kip Macy <kip.macy at gmail.com> wrote:

> The man pages have a fair amount of documentation, you can also look
> dev/hwpmc/pmc_events.h to find all the event names.
>
> -Kip
>
> On Thu, Jan 15, 2009 at 12:23 PM, carl tropper <carl at cs.mcgill.ca> wrote:
> >
> > What are the performance counters for multicore (unix based) machines
> which
> > are relevant to cache behavior? I am interested in determining the amount
> of
> > performance loss due to cache misses.
> >
> >
> > Carl Tropper
> > Department of Computer Science
> > McConnell Engineering Building
> > McGill University
> > Montreal, Canada, H3A 2A6
> > tel: (514)398-3743
> > fax: (514)398-3883
> > url:www.cs.mcgill.ca/~carl <http://www.cs.mcgill.ca/%7Ecarl>
> >
> >
>

Carl,

  If you are worried by portability (you just talk about "unix based"), you
can also consider PAPI (http://icl.cs.utk.edu/papi). It provides a layer
built on top of the different available substrates related with performance
counters. For example, it works on FreeBSD on top of libpmc, in Linux on top
perfctr and/or perfmon and in AIX on top of PMAPI.

  PAPI tries to simplify some performance metrics because the CPU typically
provides counters highly-related with its architecture, for example I've
seen AIX/PowerPC machines that provide cache misses for level 2.5 and 2.75
which is quite peculiar. PAPI is also able to provide direct access to them,
if you are interested.

  If you just consider FreeBSD (as you contacted this list), you may
directly look for the hwpmc and pmc entry manuals.

Regards,