topic Re:Collecting OpenMP regions with Intel Trace Collector in Intel® MPI Library

Collecting OpenMP regions with Intel Trace Collector

Noe-Ohana — Tue, 22 Dec 2020 19:47:56 GMT

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?

Re:Collecting OpenMP regions with Intel Trace Collector

AbhishekD_Intel — Tue, 29 Dec 2020 08:34:50 GMT

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

Re:Collecting OpenMP regions with Intel Trace Collector

Kevin_O_Intel1 — Wed, 30 Dec 2020 15:05:48 GMT

Can you attach the trace you collected?

Re:Collecting OpenMP regions with Intel Trace Collector

Kevin_O_Intel1 — Mon, 04 Jan 2021 14:31:29 GMT

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

Re: Re:Collecting OpenMP regions with Intel Trace Collector

Noe-Ohana — Mon, 04 Jan 2021 14:42:20 GMT

Sure, here it is.

Thank you very much for having a look into it.

Re: Re:Collecting OpenMP regions with Intel Trace Collector

Noe-Ohana — Mon, 04 Jan 2021 14:45:06 GMT

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.

Re:Collecting OpenMP regions with Intel Trace Collector

Kevin_O_Intel1 — Tue, 05 Jan 2021 13:59:58 GMT

Reviewing the result and will see if I can duplicate

Re: Re:Collecting OpenMP regions with Intel Trace Collector

Noe-Ohana — Tue, 16 Mar 2021 12:55:54 GMT

Hi.

Do you have any update on this topic?

Thanks.

Re: Re:Collecting OpenMP regions with Intel Trace Collector

Kevin_O_Intel1 — Tue, 30 Mar 2021 13:15:29 GMT

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

Re: Re:Collecting OpenMP regions with Intel Trace Collector

Kevin_O_Intel1 — Thu, 20 May 2021 18:28:23 GMT

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.

Re: Re:Collecting OpenMP regions with Intel Trace Collector

Noe-Ohana — Thu, 20 May 2021 18:38:26 GMT

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

Re: Re:Collecting OpenMP regions with Intel Trace Collector

Kevin_O_Intel1 — Thu, 20 May 2021 20:44:24 GMT

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

Re: Re:Collecting OpenMP regions with Intel Trace Collector

Noe-Ohana — Thu, 20 May 2021 20:48:33 GMT

All right, thank you very much.

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

Re: Re:Collecting OpenMP regions with Intel Trace Collector

Kevin_O_Intel1 — Fri, 21 May 2021 14:43:39 GMT

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