Hi,

    I've briefly looked through perfmon's document. It seems that perfmon provides both time-based sampling and event-based sampling. In the event-based sampling mode, a sampling is made when a preset event reaches a specific threshold. I think this is exactly what I want. That is, collect the counter values after every million instructions are retired. Also, perfmon provides two options: --long-smpl-periods and --short-smpl-periods. I believe these two options are related to the sampling period setting. Can anyone generally explain how to do a sampling in event-based mode?

   Maybe this question is sort of silly, but please, I really have no idea...

  Thanks very much,
Ying

On Wed, Jul 6, 2011 at 4:45 PM, Ying Zhang <yzhan29@tigers.lsu.edu> wrote:
Thanks Corey, I think I'll take a look at the "perf" tool first.


On Wed, Jul 6, 2011 at 4:36 PM, Corey Ashford <cjashfor@linux.vnet.ibm.com> wrote:
On 07/06/2011 12:45 PM, Ying Zhang wrote:
> Thanks for your reply, Pradeep. I am conducting my experiment on an
> Intel Xeon E5530 (Nahalem architecture) processor, and the operating
> system is Fedora 13 X86_64. Can I use perfmon on this platform?

No, because Fedora 13 is based upon the 2.6.33 kernel.  The perfmon2
patch set only works on 2.6.30 kernels and earlier.

You're better off using the newer kernel API called perf_events.
There's a user space tool that's available with Fedora 13 and later,
called "perf"  (do a "yum install perf" and you should get it).

If you want to do exactly what you are talking about instead of using
either "perf record" (for profiling) or "perf stat" (for counting
events), you will need to write the code yourself.

To write the code yourself, you could use either the raw kernel API, or
use PAPI which should make your job a little easier.

PAPI should also be available via yum in Fedora 13, I think (try "yum
install papi").

You can find the programming details of PAPI here:

http://icl.cs.utk.edu/projects/papi/wiki/PAPIC:PAPI.3

If you have specific questions about how to use PAPI, PAPI has its own
mailing list.

- Corey

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