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Virtuoso - Jobs

rrihak

Hello, I got problem when I am simulating in Virtuoso. I set for example 30 jobs and when simulation is at start everything is OK, but when simulation is finishing jobs are lower and lower, from 30 to 3 jobs and simulation time rise. So is there any way how to set that virtuoso can work with 30 jobs during the whole simulation???

         

Parents

  • When using LSCS, this is easier to control. What happens with Monte Carlo is that (by default) the total number of jobs are divided up into chunks of grouped Monte Carlo points. I can't quite see how it's got to 6200 simulations with 23 tests and 7 corners (6 plus nominal), but the key is that ADE will try to group the Monte Carlo points together to reduce the number of spectre invocations. Say that each spectre simulation runs 40 Monte Carlo points, then if some finish earlier than others, the remaining three may be dealing with their chunks of 40 each - there's no opportunity for other "jobs" to deal with them as they're pre-allocated. 

    There's an env var to try to re-distribute, but the best option is to change this setting to a fixed (lower) number than the grouped automatically - on the Monte Carlo options form:

    If you reduce the Max to a smaller number (use some judgement here - it depends on how long each individual point takes - if you set this to 1 then you get the overhead of starting spectre for each point, which is fine if the simulation takes 30 minutes, but not fine if it takes 1 second!), then you should see more active jobs throughout.

    Andrew

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  • When using LSCS, this is easier to control. What happens with Monte Carlo is that (by default) the total number of jobs are divided up into chunks of grouped Monte Carlo points. I can't quite see how it's got to 6200 simulations with 23 tests and 7 corners (6 plus nominal), but the key is that ADE will try to group the Monte Carlo points together to reduce the number of spectre invocations. Say that each spectre simulation runs 40 Monte Carlo points, then if some finish earlier than others, the remaining three may be dealing with their chunks of 40 each - there's no opportunity for other "jobs" to deal with them as they're pre-allocated. 

    There's an env var to try to re-distribute, but the best option is to change this setting to a fixed (lower) number than the grouped automatically - on the Monte Carlo options form:

    If you reduce the Max to a smaller number (use some judgement here - it depends on how long each individual point takes - if you set this to 1 then you get the overhead of starting spectre for each point, which is fine if the simulation takes 30 minutes, but not fine if it takes 1 second!), then you should see more active jobs throughout.

    Andrew

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