GUI versus command line: drasticaly different mutlithreading behaviour

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2013-12-26
2013-12-27
  • Andrey Kazak
    Andrey Kazak
    2013-12-26

    Hello, Igor and 7-zip users.

    Can you explain me a difference between command line switches:
    -m0=LZMA2 -mx=9 -ms=off -mtc=on -mmt=32
    and the following GUI options (see attached).

    If I launch compression using GUI, then 7-zip uses all 32 cores of a 32-core CPU.
    If I launch compression using command line, then 7-zip sluggishly uses all 2-3 cores of a 32-core CPU.

     
    Last edit: Andrey Kazak 2013-12-26
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  • Igor Pavlov
    Igor Pavlov
    2013-12-26

    In gui you use solid mode.
    LZMA2 in 7-Zip needs big data to use multithreading.
    Or you can reduce dictionary:
    -m0=lzma2:d20
    -m0=lzma2:d19
    -m0=lzma2:d18
    ....
    So it will use more threads even with -ms=off

     
    Last edit: Igor Pavlov 2013-12-26
  • Andrey Kazak
    Andrey Kazak
    2013-12-27

    OK. I solved the problem with
    -ms=on

    :)

    Is there any way to use
    -m0=delta2 -m1=PPMd -mx=9
    with 32 threads?

     
  • Igor Pavlov
    Igor Pavlov
    2013-12-27

    7-zip now can't use multithreading with 7z/ppmd.
    7-zip can use multithreading with zip/ppmd. But zip format doesn't support delta filter.