Fail to open large .OAS file

edited April 2018 in KLayout Support
Hi,
KLayout kept crashing when trying to open some large .OAS files on OpenSuse 13.2 sever with KLayout 0.24.9 64Bit. The file size ranged from 7GB to 15GB. It had no problem opening smaller OAS files that were 5GB or smaller. The Linux Server has 500GB of physical RAM and there was plenty of RAM left when KLayout crashed. KLayout appeared to have loaded all the content, but crashed before showing the schematics.

Any help or recommendation is highly appreciated.

Thanks,
Sean

Comments

  • edited November -1

    Hi Sean,

    did you use viewer mode?

    Run KLayout with

    klayout -ne ...
    

    to ensure it starts in viewer mode. If you're in editor mode (all the edit buttons are visible), the OASIS shape arrays will be expanded and the memory footprint will increase unpredictably. In viewer mode, the shape arrays are kept as such and memory requirement is roughly a few (2..3) times the OASIS file size.

    Apart from that sometimes there is a ulimit imposed by the system administrators. Please check whether "ulimit -aH" will show any "max memory size" limitations.

    Is there any error message you can share with us?

    Thanks,

    Matthias

  • edited November -1
    Matthias,
    Yes, the GUI is in viewer mode when I open the file. I also try using the command line klayout -ne abc123.oas and got the same result.

    I just tried opening an 8 GB oas file using command line, and klayout was reading the entire oas file, then crashed before it displayed anything. The memory usage was at 122GB when it crashed. The GUI remains open with the spinning balls, but it was all greyed out. There is no error message at all, even with the log windows.

    ulimit -aH shows Max Memory Size was unlimited.

    Thanks,
    Sean
  • edited April 2018

    Hi Sean,

    122GB for 8GB OASIS is pretty strange. It's bascially possible to have OASIS files with that data compression level, but I have not seen such a case myself (and I am viewing big OASIS files myself). I feel there is a general issue with memory fragmentation ("holes" in the memory map which happen not to be reused by smaller blocks).

    When you say "crash", do you see the program is still running? Does it consume CPU? After reading, it needs to build search structures. Usually that will be reported in a progress bar, but in certain situations, the application may look dead for some time.

    Do you have a rough idea what the hierarchy of your layout looks like? Like a big cell with many instances and/or shapes? I cannot rule out memory fragmentation issues if there are few and big containers (i.e. flat layout with one layer and many shapes).

    Kind regards,

    Matthias

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