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Multithreading not working

Rob Gregoire

I'm simulating a 15 stage SAR ADC and even though the output log indicates that 4 processors are used with multi-threading I am not getting a reduction in Elapsed Time compared to CPU time. I even tried it with a couple ADCs in parallel to make sure the ADC is big enough but I still get no improvement.

It seems to be related to the process design kit. I can simulate a similar ADC in another process and get speed improvement. I'm using IC 6. Any ideas on what to check or what would be helpful in debugging? My internet search only turned up a question from 2006 that indicated that it doesn't work with some CMOS models.

Parents

  • I suspect you are only turning on the multithreading in spectre rather than using APS. Multithreading in spectre itself was only supported for a very limited amount of the processing for a limited number of devices, and nowadays it is not supported at all (I hope that we will at some point get the simulator to abort with a clear message rather than make you think it is supposed to do something).

    Whilst it is possible to set the number of threads as a simulator option, the right way to do this is via Setup->High Performance Simulation in ADE. You should turn on "APS" and then you can set the number of threads on this form (make sure you are not also setting it on the Simulation Options Analog form).

    If you are not turning on APS, I would expect the improvement to be limited (if anything), because that is the obsoleted mode that I refer to above.

    Regards,

    Andrew.

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  • I suspect you are only turning on the multithreading in spectre rather than using APS. Multithreading in spectre itself was only supported for a very limited amount of the processing for a limited number of devices, and nowadays it is not supported at all (I hope that we will at some point get the simulator to abort with a clear message rather than make you think it is supposed to do something).

    Whilst it is possible to set the number of threads as a simulator option, the right way to do this is via Setup->High Performance Simulation in ADE. You should turn on "APS" and then you can set the number of threads on this form (make sure you are not also setting it on the Simulation Options Analog form).

    If you are not turning on APS, I would expect the improvement to be limited (if anything), because that is the obsoleted mode that I refer to above.

    Regards,

    Andrew.

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