Re: [PerfSuite-users] Using perfsuite without PAPI

[Rick K. <rk...@nc...>]

Frederique,

> I am trying to use Perfsuite to profile a multi-threaded program on a=20
> quadripro. I am particularly interested in knowing how much time a=20
> thread is spending on each processor. I believe that perfsuite can do=20
> that but I can't install PAPI (I am not root  on the quadripro and so I=
=20
> can't path the kernel with perfctr).

You're right in thinking that PerfSuite (psrun and libpshwpc) should be=20
able to do this, however you are also right in thinking that it requires=20
some other mechanism for sampling than the basic support that is availabl=
e=20
in the absence of access to the performance counters.  I am guessing that=
=20
you are on an x86 system since you mention perfctr.

PerfSuite (version 0.6.2) can access performance counters using either=20
PAPI or Perfmon, the latter being relevant to Itanium (IA-64) systems.
So if you're on an Itanium system, you don't need PAPI, you can get by=20
with using Perfmon directly.  On x86, though, you need the kernel patched=
=20
with perfctr and PAPI installed (I am guessing you know this, but just=20
clarifying).

Without any counter support, you can only do profiling and that only in=20
one of two ways: either by the profil() routine available in glibc (this=20
would be the default in such an installation, using a configuration file=20
that is called "profil.xml"), or through interval timers and interrupt
handlers that PerfSuite installs.  The itimer approach is more flexible
and can be selected using a sample XML configuration file called=20
"itimer.xml" that should be installed in PREFIX/share/perfsuite/xml/pshwp=
c

These two methods use signals to trigger the interrupt, though, and=20
signals are a process-wide mechanism, and so they are really not useful i=
n=20
the case of a multithreaded application (at least not in the present=20
versions of PerfSuite).  The counter-based techniques interrupt on counte=
r=20
overflow, and that can be kept isolated within a particular thread since=20
the underlying drivers support this.

I am guessing that this is the major problem you are running into, and=20
unfortunately I don't have a solution apart from having to patch your=20
kernel.

The other issue (not getting file/line information) I think might be=20
related to not compiling the application with symbols enabled (-g option).

Finally, about resource collection: that is done, when using the -r optio=
n=20
to psrun, for the main thread only, and does not track time spent on a=20
per-CPU basis.  So I am afraid that again, it is not what you might=20
have been hoping for.

Sorry for the bad news - please let me know if I have misunderstood the=20
question....

Rick

>=20
> I then installed perfsuite without PAPI. And I am getting some results=20
> running:
>=20
> $ psrun -r -p myprogram
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> The resulting files are for example myprogram.*.19416.mymachine.xml and=
=20
> also myprogram.19416.mymachine.res.xml.
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> When I watch the results with psprocess
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> $ psprocess -e myprogram myprogram.*.19416.mymachine.xml
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> I get this:
>=20
>=20
> File Summary
> -----------------------------------------------------------------------=
---------Samples=20
>    Self %  Total %  File
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>     1519  100.00%  100.00%  ??
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> Function Summary
> -----------------------------------------------------------------------=
---------Samples=20
>    Self %  Total %  Function
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>     1519  100.00%  100.00%  ??
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> Function:File:Line Summary
> -----------------------------------------------------------------------=
---------Samples=20
>    Self %  Total %  Function:File:Line
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>     1519  100.00%  100.00%  ??:??:0
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> So there is no detail.
>=20
> And when I watched the resource utilization, I get this:
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> $ psprocess myprogram.19416.mymachine.res.xml
> CPU time (user, seconds)     : 3.69
> CPU time (system, seconds)   : 0.10
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> but there is no distinction between CPUs and no distinction between thr=
eads.
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> Is there any way for me to get more information using perfsuite without=
=20
> PAPI than what I already have now? Especially with the names of files,=20
> functions and the function lines?
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> Is there a way to get the time spent by each thread on each processor?
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> Thank you,
> Fr=E9d=E9rique.
>=20