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[Solved] Use of multi-core for compiling on Windows for MSVC



  • I am wondering, if there is not a way to compile with MSVC on Windows and using multiple cores.
    I had to compile Qt on Linux a couple of times lately. The use of multiple cores with "make -j<x>" came in quite handy. Today I have configured a cross-compile with "nmake -j<x>" and nmake complained. Now the compilation takes for ever while 3 of 4 cores are idle.

    What am I missing?



  • native nmake does not support this - unfortunately.

    There is a modified version, called "jom", made by our beloved Trolls. Some infos in this older blog post "Speeding up Visual C++ Qt Builds":http://labs.qt.nokia.com/2009/03/27/speeding-up-visual-c-qt-builds/ and in the gitorious repos at http://qt.gitorious.org/qt-labs/jom



  • Have you tried to build Qt to see how many cores are used?
    Since with my system the VS2010's nmake by default is using both the cores available, so i guess you don't need anything.



  • @Volker
    Thanks for hint. I will follow up.

    @Zlatomir
    I am using VS2005 on Win7 (64bit). In general I can use the parallel building process with my own source.
    The Qt compilation I am doing from the command prompt after using configure. There you have to start nmake and that is the point I got stuck.



  • Then use jom, or for VS2005 you can also add -MP to the QMAKE_CFLAGS from qmake.conf file located in mkspecs\win32-msvc2005
    //i didn't try this - because i didn't use that VS and 2010 use both my cores by default



  • For those of you looking for the same solution.
    [quote author="Volker" date="1305107505"]
    There is a modified version, called "jom", made by our beloved Trolls. Some infos in this older blog post "Speeding up Visual C++ Qt Builds":http://labs.qt.nokia.com/2009/03/27/speeding-up-visual-c-qt-builds/ and in the gitorious repos at http://qt.gitorious.org/qt-labs/jom[/quote]

    Go directly to the gitorious repos. The download link on the blog delivers an old exe.
    Or use the "FTP site directly":ftp://ftp.qt.nokia.com/jom/

    It works great !!!

    A suggestion for Qt: Include it in the distribution.



  • <Zlatomir>

    I have tried both nmake (VS2010) and jom.

    jom keeps the laptop doing some 100% usage almost all the time.

    nmake was not able to do more than 35% at any time and was doing 20% most of the times.

    i got a i7 with 8 cores, all engaged 100% and even the fan on the back of the laptop.

    jom is good, .. so jom.

    regards-


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