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VPI profiling and debugging

Erik Vermij

Hi All,


I'm working on a project consisting out of a VHDL/Verilog part and several C++ classes around it, communication using VPI. I compile using NCVerilog and run using NCSim (08.20-s201).

I've two problems here:

1) Typically I have to run for a long time, 10s of millions of cycles. Every now and then a 'ncsim internal error' in a VPI method occurs with zero useful information. Since my code does the same over and over, I don't understand why it would crash all of the sudden. Are there ways to get more information out of NCSim regarding such crashes? Or is it 'normal' that NCSim crashes every now and then? The stack trace often names 'vpi_scan' or 'vpi_iterate'.

2) Is it possible to get VPI performance profiling information out of ncsim? Just attaching perf does not produce so much useful information. In a very old post I found that adding '+ncprofile' should produce performance results, but that does not seem to work (any more?). What would be the preferred way to do this in a modern ncsim?

Thanks a lot,

Erik

Parents

  • Dear Steve,

    thanks for your quick reply. Your hint towards memory corruption made me found a missing free() on an vpi iterator. It seems to work stable now (so far).


    I wasn't aware we're using such an old version of ncsim, I've to look into that.


    Thanks,

    Erik

Reply

  • Dear Steve,

    thanks for your quick reply. Your hint towards memory corruption made me found a missing free() on an vpi iterator. It seems to work stable now (so far).


    I wasn't aware we're using such an old version of ncsim, I've to look into that.


    Thanks,

    Erik

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