what do you guys do if Synopsys DC says it runs out of memory?

Discussion in 'VHDL' started by walala, Oct 2, 2003.

  1. walala

    walala Guest

    Dear all,

    This might be more towards synthesis...

    I keep getting "run out of memory" error message from my Synopsys Design
    Compiler... The strangest thing is that the same design, sometimes can pass,
    sometimes will fail "running out of memory"... Sometimes the "memory value"
    is 4GB, sometimes it is 1GB...

    Here is my script file and here is my error message... What do you guys do
    when you meet with such problem? Could you share with some of your
    experiences?

    Thanks a lot

    -Walala

    ---------------------------------------------------------
    Script:

    $SYNOPSYS/sparcOS5/syn/bin/dc_shell-t <<!
    redirect myidct_zero1cmu.log {
    analyze -format vhdl -lib WORK {myidct_zero1cmu.vhd}
    elaborate myidct_zero1cmu -arch "flex" -lib WORK -update
    ungroup -all -flatten
    create_clock "CLK" -name "CLK" -period 60
    compile -map_effort medium -area_effort high
    current_design .
    report_timing -path full -delay max -max_paths 1 -nworst 1 >
    reports/\$current_design.rep
    report_area >> reports/\$current_design.rep
    report_resources -hierarchy >> reports/\$current_design.rep
    write -format vhdl -hierarchy -output "mapped/\$current_design.vhd"
    write -format verilog -hierarchy -output "mapped/\$current_design.v"
    echo "\nScript Done\n"
    echo "\nChecking Design\n"
    check_design
    }
    !

    -------------------------------------------------------------

    Error message:

    90 > ./scripts/myidct_zero1cmu.scr

    Behavioral Compiler (TM)
    DC Professional (TM)
    DC Expert (TM)
    DC Ultra (TM)
    VHDL Compiler (TM)
    HDL Compiler (TM)
    Library Compiler (TM)
    Power Compiler (TM)
    DFT Compiler (TM)
    BSD Compiler
    DesignWare Developer (TM)
    DesignPower (TM)

    Version 2001.08-SP2 for sparcOS5 -- Feb 05, 2002
    Copyright (c) 1988-2001 by Synopsys, Inc.
    ALL RIGHTS RESERVED

    This program is proprietary and confidential information of Synopsys, Inc.
    and may be used and disclosed only as authorized in a license agreement
    controlling such use and disclosure.

    Initializing...
    dc_shell-t>

    Out of memory.
    (Memory allocated = 4103759 K bytes)
     
    walala, Oct 2, 2003
    #1
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  2. - Check if there are some memory limits that could be changed. In bash,
    ulimit -a
    ulimit -S -d 8000000
    In tcsh, the command is different (man tcsh, search for "limit").
    - Can you increase swap size?
    - Can you synthesize your design in small parts?
    - Can you change/lower synthesizer optimization level?
    - Are you using some structures in VHDL that take lots of space
    (e.g. generate for ...)? Could they be written differently?
    - Would it help not to use "flatten"?
    - Would it help to use low effort?
     
    Tuukka Toivonen, Oct 2, 2003
    #2
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  3. Walala, you should probably Synopsys rather than comp.lang.vhdl. Just email
    . You may need to switch to the 64-bit version of DC.
     
    Richard Iachetta, Oct 2, 2003
    #3
  4. walala a écrit :
    Modify your design. You're trying to synthesize flat a brute force
    boolean description of an 8x8 IDCT. Most synthesizers will run out of
    memory. If one doesn't then it will, once you'll add the IQUANT module
    and expect some logic optimization between the two modules ;-) IDCT is a
    quite regular algorithm, it's very easy to describe in a way that most
    optimizers will optimize very fast without any memory problem. Try a
    distributed arithmetic architecture. I worked for years on MPEG
    implementations, rewieved dozens of papers about "the best IDCT
    implementation in the world" and still believe distributed arithmetic is
    preferable, whatever your cost function is.

    Best regards,
    --
    Renaud Pacalet, GET/ENST/COMELEC/LabSoC
    Institut Eurecom BP 193, 2229 route des Cretes
    F-06904 Sophia-Antipolis Cedex
    Tel : +33 (0) 4 9300 2770
    Fax : +33 (0) 4 9300 2627
    Fight Spam! Join EuroCAUCE: http://www.euro.cauce.org/
     
    Renaud Pacalet, Oct 3, 2003
    #4
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