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Giannis_G_
Beginner
548 Views

Intel PCM API in C

Hello,

I want to ask something simple yet important for me. Is there a C-language API to use instead of the C++ API that is provided for PCM?

If not (which probably is the case), is there any way to make the C++ API provided work inside a C source file?

Thanks in advance,

Giannis

P.S. Re-write the existed code in C++ and use the API provided is not a realistic option.

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6 Replies
Roman_D_Intel
Employee
548 Views

Hi Giannis,

you can look into https://github.com/opcm/pcm/tree/master/pcm.so

It provides an example that exports some of the APIs to C. Hopefully you can extend it with the calls you need.

Thanks,

Roman

Giannis_G_
Beginner
548 Views

Tried to compile and run the source code (into https://github.com/opcm/pcm/tree/master/pcm.so) that you suggested but I keep getting either a seg fault if I run without any arguments provided (run ./c_example.x) or the following error if any argument is provided:

Event 'something' is not supported. See the list of supported events

I probably cannot understand the switch statement block of code so an example would be very beneficial

Thanks again,

Giannis

Patrick_L_Intel
Employee
548 Views

Hi Giannis,

Thanks for trying. The argument syntax for c_example.x is the same as pcm-core.x. You can use ./pmu-query.py to get some example for encoding CPU counter events. It's the same syntax as Linux perf.

For example: ./c_example.x cpu/umask=0x01,event=0x48,name=L1D_PEND_MISS.PENDING/

We will update documentation soon. Thanks for your feedback.

Patrick

Giannis_G_
Beginner
548 Views

Hi again guys,

your answers so far have been proved to be very helpful, so here I am to receive some more guidelines.

Straight to the point, I've extended the example in pcm/pcm.so directory in order to support cache function calls (L2/L3 hits, misses and ratios).

I've also made the necessary adjustments in pcm/pcm-core.cpp to support that functionality.

The problem is that the result is always 0 cache hits and misses.

Any thoughts on that? What could be wrong?

P.S. I hadn't been able to run pcm/pcm-memory.x (Access to Processor Counter Monitor has denied (no MSR or PCI CFG space access)), even though pcm/pcm.x and pcm/pcm-core.x run without any error. 

Thanks in advance

Vincent_H_1
Beginner
548 Views

Giannis G. wrote:

Hi again guys,

your answers so far have been proved to be very helpful, so here I am to receive some more guidelines.

Straight to the point, I've extended the example in pcm/pcm.so directory in order to support cache function calls (L2/L3 hits, misses and ratios).

I've also made the necessary adjustments in pcm/pcm-core.cpp to support that functionality.

The problem is that the result is always 0 cache hits and misses.

Any thoughts on that? What could be wrong?

P.S. I hadn't been able to run pcm/pcm-memory.x (Access to Processor Counter Monitor has denied (no MSR or PCI CFG space access)), even though pcm/pcm.x and pcm/pcm-core.x run without any error. 

Thanks in advance

Was this issue solved? I'm also getting 0 cache hits and misses.

Chandra_V_
Beginner
548 Views

Dear Giannis and Friends,

Do you have any update on this topic. If I understand correctly c_example.c compiled on Linux platform. I have tried to compile on Windows  using Visual studio 2017 and Clion using Mingw-w64 on both instance  getting error (something missing inside )  Header files.

Please refer the attached screen shot. Any thoughts - very useful. I am struggling to get basic idea of this program. If it compiled correctly , can i use like perf (Linux) command on windows?

Many thanks.

With regards,c

handra

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