Discussion in 'Cadence' started by Arnold, Jan 13, 2005.

  1. Arnold

    Arnold Guest


    I am using Diva as checking tool for DRC and LVS.
    Do someone know, how many memory (RAM) is necessary
    for a specific size of a design ?
    I have the problem, that the EXTRACT/LVS does not finish,
    and we get the message that cadence need more memory.
    (sometimes only 10 to 200 Bytes more)
    Our workstation has now 8 GByte of RAM, and it is still
    not enough.

    Arnold, Jan 13, 2005
  2. Ignore the amount it tells you it needs. That's the memory allocater
    telling you how big an allocation it was just asked for. Completely
    meaningless information.

    Information, please. Which is not finishing? Extract or LVS? They are
    different binaries. Different steps in the flow. How many devices does
    your design have in it? What version are you running? What OS?

    In general, DRC and Extract use very little memory, except during the
    geomConnect rule. I've run 500K device designs on my 1 gig UltraSparcII.
    What is your VM size before you start the Extract? That's how much
    memory the database and graphic editor are using, which may not leave
    Diva much to work in. Flatten the 500K device design and there is not
    much left.

    LVS can be very memory intensive. The memory usage starts proportional
    to the number of nets, devices, device pins and device property
    characters. Then the logic combination process starts making meta
    devices. The meta devices take space, as does the undo information
    needed for error reporting from the meta devices. This makes it hard to
    predict memory usage of LVS. If your circuit combines into logic
    functions really well, it can double or triple the memory usage.

    Both DRC/Extract and LVS can run in 64bit mode to take advantage of the
    extra RAM. I would monitor the run using the top utility to see how much
    VM the process is using when it fails. Some workstations have small VM
    quotas for some reason only IT seems able to understand.

    As always, I'll be happy to see a bug report come in for any Diva
    problem. Just submit everything, through your FAE, needed to reproduce
    the problem. We can work on problems like this blind, but who knows if
    it will fix *your* particular problem.
    Diva Physical Verification, Jan 14, 2005
  3. Arnold

    John Gianni Guest

    In addition, for what it's worth, the Cadence system configuration
    checker (checkSysConfig) shipped with every release of every tool at
    Cadence for the past few years tells you the MINIMUM memory required to
    run the tool.

    I fought for years to get this tool to Customers and I'm glad it is now
    available to Customers ... however ... bluntly stated, while it does
    patch levels rather well, it doesn't do a whole lot for memory and swap

    Still, it's something you should run BEFORE you run Diva (or any
    Cadence tool).

    You can pick up the latest checkSysConf Cadence System Configuration
    Checker on Sourcelink.

    John Gianni
    John Gianni, Jan 14, 2005
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