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Luis Alvarado
Asked: 2012-02-24 08:53:29 +0800 CST

How to speed up compilation of Ubuntu apps (make, cmake, gcc)

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I am compiling some programs here and I have 4 cores. Is there a way to tell make, cmake or gcc to compile using all cores or something to that affect?

compiling gcc 11.10 make

1 Answers

  1. Best Answer

    If a package supports it you can use the -j flag to allow parallel jobs running, e.g.:

    make -j8

    More details on this flag can be found in the Stackoverflow question Why does make -j perform better when it is passed a number larger than the number of cores available?.

    Distributed compilation

    If you have multiple machines, give distcc a go. On the involved machines, sudo apt-get install distcc. Assuming that your build machine is 192.168.1.1:

    • on the helper machines, run:

      sudo distccd --log-file=/tmp/distccd.log --daemon -a 192.168.1.1

    • On the build machine, before running configure or cmake you have to specify hosts that you want to use for the build process. Optionally, specify the number of simultaneous jobs after a slash (defaulting to 4):

      export DISTCC_HOSTS='localhost/4 192.168.1.2/8 192.168.1.3/8'

      Make the compiler use distcc:

      export PATH="/usr/lib/distcc:$PATH"

      Now configure or cmake the application and build with:

      make -j$(distcc -j)

      Note that if you've put /usr/lib/distcc twice in your PATH, it'll fail. Be sure to set /usr/lib/distcc only once in your PATH.

    For more details, see the manual pages for distcc(1) and distccd(1).

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