Re: [PerfSuite-users] problem about profiling fortran program with libpshwpc

[George M. <ge...@ma...>]

Dear Rick,

First of all thanks for the help, it was a simple problem but because I am
trying a lot of stuff I forgot about it. The problem is solved.
About my second question. Basically I want to measure only two hardware
counters PAPI_FP_OPS and PAPI_TOT_CYC in order to take Mflops. I ask about
how accurate it is because I compared results from profiling matrix
multipication (C, MPI, ScalaPack with psrun) with another profiling tool and
with perfsuite I had 960 mflops per cpu but with the other one almost 1020
mflops. Multiplexing was enabled, so is it possible to loose so many flops?
Also PerfSuite measure also MPI command's flops (all_reduce etc?). I was
trying to figure out why there was such a difference. If PerfSuite use
statistical sampling then it is possible to loose some data?

Best regards,
George Markomanolis

On Thu, Jun 11, 2009 at 8:17 PM, Rick Kufrin <rk...@il...> wrote:

> George,
>
> Hopefully this is a simple problem to fix: my guess is that you configured
> and built PerfSuite with a different Fortran compiler than the one you are
> using to compile the NAS benchmarks.  For example, you configured using the
> default Fortran compiler (typically GNU g77 or gfortran) but built the
> benchmarks with Intel's ifort compiler.  If this is the case, then try
> reconfiguring and building PerfSuite, this time specifying a compiler
> explicitly with the variable F77.  E.g.,
>
> $ ./configure --prefix=XXX --with-papi=XXX F77=ifort
>
> If this doesn't solve the linking problem, please let us know.
>
> Regarding the second question: I think you may be referring to two
> different modes of operation here.  When doing profiling, PerfSuite does
> indeed use statistical sampling.  This usually requires a user-selected
> configuration file, though, one with the document type <ps_hwpc_profile>.
>  When simply counting the total number of event occurrences (which is where
> the term "multiplexing" applies), you have some control over whether
> multiplexing is used based on the number of events you've requested.  If you
> only request a few events, you are more likely to get a non-multiplexed run.
>  If it doesn't detect that it needs to, PerfSuite will avoid enabling
> multiplexing. You can always check whether multiplexing was enabled by
> looking at the output of "psprocess" or viewing the output XML document
> directly.  Probably the shortest route to what you need is to use a
> configuration file that only requests PAPI_FP_OPS or PAPI_FP_INS. There are
> a number of example configuration files installed in the directory
> $PREFIX/share/perfsuite/xml/pshwpc that may help in writing a new one that
> fits your needs.
>
> Hope that helps clear things up.
>
> Rick
>
> George Markomanolis wrote:
>
>> Dear all,
>>
>> I am sending you an email because I have a problem to profile a fortran
>> program with libpshwc. I can profile the program with psrun but because I
>> want to profile specific blocks of the code only, I would like to use
>> |PSF_hwpc_init(ierr) |etc.  The program is one from NAS Parallel benchmarks
>> (FT) and when I compile it I see the errors
>>
>> ft.f:(.text+0x24): undefined reference to `psf_hwpc_init_'
>> ft.f:(.text+0x76): undefined reference to `psf_hwpc_start_'
>> ft.f:(.text+0x2b7): undefined reference to `psf_hwpc_stop_'
>> ft.f:(.text+0x471): undefined reference to `psf_hwpc_shutdown_'
>>
>> ||I have included fperfsuite.h and I have linked with -lpshwpc -lperfsuite
>>
>> Could you propose something to solve my problem?
>> Also a simple question: I am confused, PerfSuite measures with statistic
>> sampling? I now that with multiplexing is less accurate. I ask because I
>> want to count flops and I don't want to loose any info.
>>
>> Thanks in advance,
>> Best regards,
>> George Markomanolis
>>
>>
>>
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>
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