Re:Profiling FPGA code with Vtune

[Mickleman]

Many thanks Stas

That works perfectly.  I can now run my FPGA application through Vtune on a local Linux browser.  I will try the VS Code route later.  I look forward to reading your cookbook.

My next problem is that the application fails at kernel launch if I select AOCL Profiler (it works for OpenCL Profiling API but gives no details on the kernel performance).  The application is compiled with -Xsprofile.  The error logged is:

acl_profiler.cpp:831 int acl_process_profiler_scan_chain(acl_device_op_t*): Assertion '0' failed.
aocl Error: The execution failed with an error.
aocl Returned status: 6

What am I doing wrong?

Kind regards
Marcus

[Dmitry_R_Intel1]

This looks like a known bug which is planned to be fixed in next releases. As for workaround passing “-no-mem-transfers" option to aocl profile should help. This corresponds to 'FPGA no memory transfers' option in VTune analysis configuration. This does mean that memory transfer information between device and host will not be present in the final VTune report though.

[RaeesaM_Intel]

Hi ,

Did you try the solution provided by Dmitry. Is your issue resolved ?

Please let us know the updates.

Raeesa

[Mickleman]

Hi Raeesa and thanks Dimitry.

Yes this work-around works.  But I still don't see any detailed performance figures within the FPGA kernel - what information should I expect to see?

Marcus

[RaeesaM_Intel]

Hi Marcus,

Glad to know that work-around worked for you.

Please refer the following link for details regarding FPGA analysis and viewpoints :

https://software.intel.com/content/www/us/en/develop/documentation/vtune-help/top/analyze-performance/accelerators-group/cpu-fpga-interaction-analysis/cpu-fpga-interaction-view.html#cpu-fpga-interaction-view_FPGA

Hope this helps.

Thanks and Regards,

Raeesa

[Mickleman]

Hi Raeesa,

I'm afraid I am still struggling to see any FPGA results.  The documentation you refer to says to look at the 'FPGA Top Compute Tasks' section of the Summary.  But this does not exist.  Neither does the 'Bottom-up' window.

In the Configuration I have chosen 'CPU/FPGA Interaction', left everything as default except for ticking the 'FPGA no memory transfers' as instructed.   Is there something else I need to do?

I attach the collection log which contains warnings in case there is a clue there.

Kind regards
Marcus

[Dmitry_R_Intel1]

Could you please archive and share the VTune result folder (e.g. the r010fi one)? If you can't do this please share at least the log and config folders from it (e.g. r010fi/log and r010fi/config). 

[Mickleman]

Hi Dmitry

Here is result folder.

Marcus

[Dmitry_R_Intel1]

The error from logs is essentially saying that the compiler produced a profiler config file but did it wrong – a bug we haven’t seen before. If you can provide the application binary (target-forward.fpga) it would be a huge help in debugging. Feel free to contact me by mail Dmitry.Ryabtsev@intel.com if you prefer to do it privately.

[Dmitry_R_Intel1]

We've got the binary and will continue the investigation. Meanwhile you can try the following things:

1) Run the design using “aocl profile /home/u57941/target-forward/target-forward.fpga” and see if it also produce the same errors

2) Recompile the design using the -Xsprofile option in case their design executable (target-forward.fpga) is corrupt in some way and then run step 1)

[Dmitry_R_Intel1]

After some investigation we discovered a bug in the compiler that was resulting in a debug location having a line number of 0. This caused the profiler post processor to fail while trying to parse the line number. We plan to fix it in next versions of compiler. 

[DMITRY_T_Intel]

Hi Marcus,

This issue escalated to development. I will let you know as soon as I get any information.

Thank you!

[DMITRY_T_Intel]

Hi Marcus,

This issue was fixed in oneAPI 2021.4 release which will be available for download soon. If you need any additional information, please post a new question as this thread will no longer be monitored by Intel.

Thank you very much!