Collecting OpenMP regions with Intel Trace Collector

[Noe-Ohana]

I am trying to follow the steps from Intel Trace Collector documentation for collecting data about OpenMP regions.

I must be missing something because the resulting trace does not contain any OpenMP information:

I am working on Windows, with Fortran code. I have Intel Parallel Studio XE 2020 Update 2 Cluster Edition for Windows, and Visual Studio 2017.

Here is how I compile and link the code:

> ifort -Qopenmp -trace -openmp -c test.f90
> Link /OUT:test.exe /LIBPATH:"%VT_ROOT%\dll" /SUBSYSTEM:CONSOLE VT.lib impi.lib test.obj

And here is how I run it:

mpiexec -trace -n 2 -genv OMP_NUM_THREADS=8 -genv INTEL_LIBITTNOTIFY64="%VT_ROOT%\dll\VT.dll" test.exe

Does anyone have any idea what could go wrong?

[AbhishekD_Intel]

Hi,

Thanks for reaching out to us.

We tried your code sample and we are also getting the same result with ITAC, so we are forwarding this issue to the concerned team.

Warm Regards,

Abhishek

[Kevin_O_Intel1]

Can you attach the trace you collected?

[Noe-Ohana]

Sure, here it is.

Thank you very much for having a look into it.

[Kevin_O_Intel1]

You should also verify the program is actually running with openmp.

[Noe-Ohana]

The program is indeed running with OpenMP. I can see it in the code output (Hello world from each thread), and even the collected trace detects 2 processes and 16 threads. It simply does not instrument the OpenMP regions.

[Kevin_O_Intel1]

Reviewing the result and will see if I can duplicate

[Noe-Ohana]

Hi.

Do you have any update on this topic?

Thanks.

[Kevin_O_Intel1]

I will give an update as soon as I can reproduce. Checking

[Kevin_O_Intel1]

Did you try using the directions documented https://software.intel.com/content/www/us/en/develop/documentation/itc-user-and-reference-guide/top/user-guide/recording-openmp-regions-information.html

Windows* OS

• Your application should be:
• linked with the Intel implementation of OpenMP.
• dynamically linked with the 

  VT.dll

   library and Intel MPI Library.
• The example command line to compile the application may look as follows:

  > mpiicc -trace -openmp myapp.c
• Make sure the 

  INTEL_LIBITTNOTIFY64

   environment variable contains the full path to the 

  VT.dll

   library.
• Run your application using the 

  mpiexec

   command to trace the data.

[Noe-Ohana]

Thank you for coming back to me.

Those are the directions I have tried to follow.

Do you mean that the issue does not reproduce on your side? Are you doing anything differently?

From the original post:

Here is how I compile and link the code:

> ifort -Qopenmp -trace -openmp -c test.f90
> Link /OUT:test.exe /LIBPATH:"%VT_ROOT%\dll" /SUBSYSTEM:CONSOLE VT.lib impi.lib test.obj

And here is how I run it:

mpiexec -trace -n 2 -genv OMP_NUM_THREADS=8 -genv INTEL_LIBITTNOTIFY64="%VT_ROOT%\dll\VT.dll" test.exe

---

[Kevin_O_Intel1]

My results are slightly different ...~75% serial 25% MPI calls 0% OMP

I believe this is because loops might be happening too fast for us to collect any samples... but I will verify with team

[Noe-Ohana]

All right, thank you very much.

I have tried to profile a real application the same way, and I always get 0s in OpenMP.

[Kevin_O_Intel1]

Actually, I think you are right... this looks like a bug to me. I am filing a bug report and we will try to fix in a later version.

Thank you very much for reporting the issue.

Regards