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ADE-XL: How to force individual result directories for each Monte Carlo point?

dontpanic

Hi! I am having an issue with the way ADE-XL (6.1.6-64b.500.11) is treating the results directories when running Monte Carlo simulations.

I have in my testbench a custom VA component that samples and dumps signals to the disk. For example, if I run a simulation in "Single run, sweeps and corners" mode with 3 corners, my dumped results are stored in the following directories and files:

[...]/[my_lib]/[my_cell]/adexl/results/data/Interactive.7/1/sch__noiseless/psf/myDumpedSimData/vOUTdiff.csv
[...]/[my_lib]/[my_cell]/adexl/results/data/Interactive.7/2/sch__noiseless/psf/myDumpedSimData/vOUTdiff.csv
[...]/[my_lib]/[my_cell]/adexl/results/data/Interactive.7/3/sch__noiseless/psf/myDumpedSimData/vOUTdiff.csv

The problem is when I switch to "Monte Carlo Sampling" mode. For instance, if I run 48 MC points for only 1 corner (and setting in my Job Setup options "Max. Jobs"=8), I see the following directories are being created:

[...]/[my_lib]/[my_cell]/adexl/results/data/MonteCarlo.3/1/sch__noiseless/groupRunDataDir/psf/myDumpedSimData/vOUTdiff.csv
[...]/[my_lib]/[my_cell]/adexl/results/data/MonteCarlo.3/1/sch__noiseless/groupRunDataDir/psf/myDumpedSimData/vOUTdiff.csv~

[...]/[my_lib]/[my_cell]/adexl/results/data/MonteCarlo.3/7/sch__noiseless/groupRunDataDir/psf/myDumpedSimData/vOUTdiff.csv
[...]/[my_lib]/[my_cell]/adexl/results/data/MonteCarlo.3/7/sch__noiseless/groupRunDataDir/psf/myDumpedSimData/vOUTdiff.csv~

[...]/[my_lib]/[my_cell]/adexl/results/data/MonteCarlo.3/13/sch__noiseless/groupRunDataDir/psf/myDumpedSimData/vOUTdiff.csv
[...]/[my_lib]/[my_cell]/adexl/results/data/MonteCarlo.3/13/sch__noiseless/groupRunDataDir/psf/myDumpedSimData/vOUTdiff.csv~

[...]/[my_lib]/[my_cell]/adexl/results/data/MonteCarlo.3/19/sch__noiseless/groupRunDataDir/psf/myDumpedSimData/vOUTdiff.csv
[...]/[my_lib]/[my_cell]/adexl/results/data/MonteCarlo.3/19/sch__noiseless/groupRunDataDir/psf/myDumpedSimData/vOUTdiff.csv~

[...]/[my_lib]/[my_cell]/adexl/results/data/MonteCarlo.3/25/sch__noiseless/groupRunDataDir/psf/myDumpedSimData/vOUTdiff.csv
[...]/[my_lib]/[my_cell]/adexl/results/data/MonteCarlo.3/25/sch__noiseless/groupRunDataDir/psf/myDumpedSimData/vOUTdiff.csv~

[...]/[my_lib]/[my_cell]/adexl/results/data/MonteCarlo.3/31/sch__noiseless/groupRunDataDir/psf/myDumpedSimData/vOUTdiff.csv
[...]/[my_lib]/[my_cell]/adexl/results/data/MonteCarlo.3/31/sch__noiseless/groupRunDataDir/psf/myDumpedSimData/vOUTdiff.csv~

[...]/[my_lib]/[my_cell]/adexl/results/data/MonteCarlo.3/37/sch__noiseless/groupRunDataDir/psf/myDumpedSimData/vOUTdiff.csv
[...]/[my_lib]/[my_cell]/adexl/results/data/MonteCarlo.3/37/sch__noiseless/groupRunDataDir/psf/myDumpedSimData/vOUTdiff.csv~

[...]/[my_lib]/[my_cell]/adexl/results/data/MonteCarlo.3/43/sch__noiseless/groupRunDataDir/psf/myDumpedSimData/vOUTdiff.csv
[...]/[my_lib]/[my_cell]/adexl/results/data/MonteCarlo.3/43/sch__noiseless/groupRunDataDir/psf/myDumpedSimData/vOUTdiff.csv~

So even though all the 48 MC points run without problems, ADE-XL is arranging/processing the results directories in a way that the files with the dumped signals are being overwritten, and in the end I am only left with 8 individual "vOUTdiff.csv" files (+8 old "vOUTdiff.csv~").

The root of the problem seems to be in the way the simulations are being launched, since in the individual spectre.out logs I see the warnings coming from my VA code messages about the files being overwritten (see attached excerpt below), and also that the MC points are being treated as "iterations".

How can I avoid this behavior, and force ADE-XL/spectre to keep the individual results directories for every MC point, while being able to run many MC points in parallel?

Thanks in advance for any help!

Cheers,

Jorge

Parents
  • Andrew Beckett

    Frank,

    I'm not convinced that this is a bug anyway. The same thing happens when using any kind of built-in sweep in the simulator (and monte carlo is just one example of that) - the VerilogA model is just overwriting the same file each time.

    All the the pre-run script does is to force spectre to be run with single-point monte carlo runs. You don't want that in general, because it's less efficient because you end up with more invocations of the simulator, more time spent reading the netlist and checking out licenses.

    Now, if there was a way to generate a unique filename in each monte carlo point run, then that would be the best solution, in my opinion. You ought to be able to use something like this (I think):

    fp=$fopen("./fixedname%A.txt","w");

    but from my quick experiment, I get an error saying that too many files have been open:

    Fatal error found by spectre at iteration = 2 during DC analysis `mc-002_dcOp',
    during Monte Carlo analysis `mc'.
    FATAL (ASL-3246): "monte.va" 9: MON1: Failed to run the simulation because
    one Verilog-A $fopen statement has been used to open more than one
    file. The number of $fopen statements should be more than the number of
    files to be opened. Specify the correct number of $fopen statements and
    rerun the simulation.

    I do have a $fclose in my case - so I'm not really sure why it is reporting this. I'll ask R&D.

    Regards,

    Andrew.

Reply
  • Andrew Beckett

    Frank,

    I'm not convinced that this is a bug anyway. The same thing happens when using any kind of built-in sweep in the simulator (and monte carlo is just one example of that) - the VerilogA model is just overwriting the same file each time.

    All the the pre-run script does is to force spectre to be run with single-point monte carlo runs. You don't want that in general, because it's less efficient because you end up with more invocations of the simulator, more time spent reading the netlist and checking out licenses.

    Now, if there was a way to generate a unique filename in each monte carlo point run, then that would be the best solution, in my opinion. You ought to be able to use something like this (I think):

    fp=$fopen("./fixedname%A.txt","w");

    but from my quick experiment, I get an error saying that too many files have been open:

    Fatal error found by spectre at iteration = 2 during DC analysis `mc-002_dcOp',
    during Monte Carlo analysis `mc'.
    FATAL (ASL-3246): "monte.va" 9: MON1: Failed to run the simulation because
    one Verilog-A $fopen statement has been used to open more than one
    file. The number of $fopen statements should be more than the number of
    files to be opened. Specify the correct number of $fopen statements and
    rerun the simulation.

    I do have a $fclose in my case - so I'm not really sure why it is reporting this. I'll ask R&D.

    Regards,

    Andrew.

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