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Data Retrieval after long simulation

Flyyn Rider

Hi,

I have run into this problem for the third consecutive time. I ran 24,000 simulations of my 12 bit SAR ADC to compute it's INL and DNL plots. I am sweeping a desig variable across a corner for 24,000 times. My output is just the output of ADC which is its 12 bits for every simulation (which i use to compute it's analog equivalent value,X, a number). So after all simulations I should get linear response (stair case actually) with X on yaxis and varied variable on xaxis. My problem is: when all the simulations are complete the ADE XL window and CIW window freeze/go blank.  Here is some information:

1. Last simulation,24000th, completed on 7:30PM 12 August and the time of writing this post is 12:15 PM 13 August. ADE XL is given enough time to populate the data and generate the stair case plot I discussed.

2. I am using Cadence IC6.1.5.500.9

3. I am only saving data for nodes of interest to save space on disk.

4. I have 16GB RAM and 4 core processor (DELL XPS core i7)

5. I ran simulation on all four cores in parallel to speed up the simulations by specifying it in the 'Job Setup' window of ADE XL.

Now since my ADEXL and CIW windows were blank so i had to kill the process. Here is what i found:

1. The process was consuming 100% of CPU usage

2. I checked the RAM before killing the process, 87MB remained out of 16GB and after killing the process the free memory is still only 1GB.

Anyway the spectre generated 32GB of data on my hard disk with the following path:

..."project directory"/adexl/results/data/interactive9/.....and in this folder i have 24000 folders of every simulation, a psf folder and shared data folder (for running jobs in parallel). The psf folder contains netlisting info for the whole cct. And every 24000 folder again contain the netlist and psf folders.

I need to know is there any thing wrong with my simulation setup? Now since I have 32 GB data how can I retrieve the staircase plot of output,X, vs input, variable?  ADEXL should generate this plot instead of going blank. It does generate it for small simulations but now after 24000 simulations since it has gone blank, do I need to wirte ocean script to retrieve such plot...Could someone suggest ocean script or some better solution? Thanks

  • Well it turns out that we can open output file by right clicking on relevant 'interactive' in the history tab of ADEXL. I wish we had an option to delete the post!!!

  • The best thing you should do is to move to IC616 ISR6 or later. There was a lot of work that went on in late IC615 ISRs, and particularly in IC616 ISR3 and 4 to address performance issues with large numbers of corners or swept points, particularly to address this "freezing" that happens at the end of simulation (we had one case that we reduced from 4 hours to 5 minutes), with further work to increase the scalability of ADE XL performance with large numbers of simulations ongoing in future IC616 ISRs and IC617. 

    You're using quite an old version, and the biggest bang for the buck would be to change versions rather than trying to come up with creative ways around the limitations. The fixes were in lots of different parts of the code as it was a big optimization task, so it is very hard to narrow down to just one thing.

    Regards,

    Andrew.

  • Thanks Andrew.

    Could you throw some light on the key differnces in MMSIM and Spectre?

    Spectre is included DFII package for IC615. Can we run MMSIM with IC615 or we need to update it to IC 616 and above? Spectre simulator package also includes 'Ultrasim' tool and APS and Turbo simulation modes in 'High Performance Simulation' options. Even so, is it true to say that MMSIM is an advanced version of Spectre and has better efficiency in simulating RF, analog, and mixed signal circuits?

    Could you tell which is the latest version of IC cadence design suite?

    Where can I such 'CAD' related info? I have searced the internet but I am a little confused. Thanks

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