Home > Community > Forums > Custom IC Design > APS, Multi-threading, High-Performance Simulation...

Email

* Required Fields

Recipients email * (separate multiple addresses with commas)

Your name *

Your email *

Message *

Contact Us

* Required Fields
First Name *

Last Name *

Email *

Company / Institution *

Comments: *

 APS, Multi-threading, High-Performance Simulation... 

Last post Thu, Jul 26 2012 8:35 AM by Rob Gregoire. 8 replies.
Started by aditeman 14 May 2012 11:26 PM. Topic has 8 replies and 7141 views
Page 1 of 1 (9 items)
Sort Posts:
  • Mon, May 14 2012 11:26 PM

    • aditeman
    • Not Ranked
    • Joined on Wed, Jul 14 2010
    • Posts 11
    • Points 160
    APS, Multi-threading, High-Performance Simulation... Reply

    Andrew,

     

    I am a bit confused with all of the high performance simulation options in ADE-XL/GXL.

    I am using IC 6.1.5.506 with  MMSIM 10.11.200

    On ADE I have:

      1. "Options->Job Setup->Max Jobs"  

       2.  "Options->Run Options-> Run In"

      3.  "High-Performance Simulation->Mode, Multithreading options, Affinity"

      4. "Options->Analog->Multithreading Options"

    Maybe others...

     

    What is the up to date way to run my simulations as fast as possible?

    The main reason I'm asking is that I've had some problems when setting things such as APS + Max Jobs=8. For example, I've had these settings and sent a small simulation with a few corners and after waiting 10 minutes it still hadn't started. In general, it seems to take minutes until simulations start running sometimes (and then they run very fast).

    Any suggestions/explanations?

     

    Thanks,

     

    ADi 

     

    • Post Points: 20
  • Tue, May 29 2012 12:36 AM

    • aditeman
    • Not Ranked
    • Joined on Wed, Jul 14 2010
    • Posts 11
    • Points 160
    Re: APS, Multi-threading, High-Performance Simulation... Reply

    Can anyone help me on this?

     

    Thanks

     

    Adi 

    • Post Points: 5
  • Tue, May 29 2012 5:29 AM

    • tkhan
    • Top 50 Contributor
    • Joined on Sat, Aug 16 2008
    • Toronto, Ontario
    • Posts 159
    • Points 2,220
    Re: APS, Multi-threading, High-Performance Simulation... Reply
    Are you running in local or distributed mode? Do you have enough licenses available?
    • Post Points: 20
  • Tue, May 29 2012 5:36 AM

    • aditeman
    • Not Ranked
    • Joined on Wed, Jul 14 2010
    • Posts 11
    • Points 160
    Re: APS, Multi-threading, High-Performance Simulation... Reply

    I can run in either local or distributed, and I have plenty of licenses, as I am a student in an academic institute and we get an enlarged package, so I don't mind using a lot of licenses. 

     

    Thanks 

    • Post Points: 20
  • Wed, Jun 6 2012 6:00 AM

    Re: APS, Multi-threading, High-Performance Simulation... Reply

      1. "Options->Job Setup->Max Jobs"  

    This controls the number of parallel simulations that may be run at once in ADE XL. If you are using multiple tests in ADE XL, or corners, or sweeping variables or parameters, each one of these counts as a "job", and they can be run in parallel (on the local machine, on a remote machine, or distributed using a queueing system). Also if using Monte Carlo, it can break up the number of monte carlo points into chunks, based on the number of available parallel runs.

      2.  "Options->Run Options-> Run In"

    This is not that useful - it's more to do if you hit the "Run" button again before existing jobs have finished - maybe having changed some setup.

      3.  "High-Performance Simulation->Mode, Multithreading options, Affinity"

    This allows an individual simulation job to take advantage of multi-core technology and do things like the matrix solve in parallel - so it can speed up an individual simulation. Processor Affinity should be left alone (it allows you to get absolutely the best performance by telling the simulator which CPUs in a multi-core machine are to be used, but this is only ever useful if you have complete control over the machine you're running on, and has to be set carefully and is not normally worth the bother of setting)

      4. "Options->Analog->Multithreading Options"

    This is pretty much obsolete nowadays - it was an earlier form of (limited) multithreadhing. It controls the same thing that's on the High Performance Options setting now - but that's the preferred location (the high performance options) to set multi-threadhing.

    Regards,

    Andrew.

    • Post Points: 35
  • Sun, Jun 10 2012 12:45 AM

    • aditeman
    • Not Ranked
    • Joined on Wed, Jul 14 2010
    • Posts 11
    • Points 160
    Re: APS, Multi-threading, High-Performance Simulation... Reply

    Thanks!

     

    Do you have any idea what could be causing a long delay to initiate simulations? In other words, I press the "run" button, and once in a while I can wait a minute or longer (sometimes I stop it out of frusteration) before the simulations actually start. I have, for example, waited over 10 minutes for a simple simulation to start, then changed servers, and had the whole simulation from start to finish take 20 seconds. Our system administrator has tried to look into it, but as it happens quite sporadically, we have no clue what could be causing it. I do have a feeling, though, that it mainly happens when I try to run on multiple CPUs...

     

    Thanks again,

    Adi 

    • Post Points: 5
  • Thu, Jul 26 2012 7:06 AM

    Re: APS, Multi-threading, High-Performance Simulation... Reply

     Hi Andrew and others,

    I am running a long sim for a delta-sigma converter. Is there an optimum number of threads to use? I have six processors available, but I seem to remember that someone saying that at some point the speed increase is minimal if you add more processors -- I just don't remember what that point of diminishing returns was. 

    Best regards,

    Rob

    • Post Points: 20
  • Thu, Jul 26 2012 8:01 AM

    Re: APS, Multi-threading, High-Performance Simulation... Reply

    Rob,

    It's quite hard to be precise about this - APS supports up to 32 cores these days - and I have customers using that number (for very large circuits - e.g. several million transistors and even larger numbers of parasitics), so your mileage may vary. Generally speaking it's bigger circuits that will benefit from more threads. Doing some quick experiments with different number of threads would allow you to assess this for your size of design. You can check the utilization figures too that are reported in the log file (bearing in mind that you really wouldn't expect it to be able to fully utiliize all threads anyway).

    Regards,

    Andrew.

    • Post Points: 20
  • Thu, Jul 26 2012 8:35 AM

    Re: APS, Multi-threading, High-Performance Simulation... Reply

    Andrew, thanks for the answer. As always, I'm am very appreciative of the time you spend here helping.

    • Post Points: 5
Page 1 of 1 (9 items)
Sort Posts:
Started by aditeman at 14 May 2012 11:26 PM. Topic has 8 replies.