DirectFB performance



  • Dear All,

    I'm use QT 4.8.7 and broadcom board.

    I want to use qt ui and directly call directfb api. (directfb version is 1.7.x)
    I could find to use both but there is lower performance problem.

    The performance is lower to call blit (directfb api) with QApplication.

    I mean 1 is twice faster than 2.

    1. call the blit function with QCoreApplication
    int main(int argc, char *args[])
    {
        QCoreApplication app(argc, args);
        DirectFBTest();
        return app.exec();
    }
    
    1. call the blit function with QApplication (-qws -display directfb)
    int main(int argc, char *args[])
    {
        int _argc = 4;
        char *_args[4] = {"test","-qws","-display","directfb"};
    
        QApplication app(_argc, _args);
        DirectFBTest();
        return app.exec();
    }
    

    Note: the function (DirectFBTest) is just rendering image and blit it to primary surface.

    Could you advise for me to improve the performace?

    Jean.


  • Lifetime Qt Champion

    Hi,

    Just an educated guess:
    Numer one is faster because there's nothing accessing the framebuffer at all while with number two there's QWS running which does use said framebuffer to do window management.



  • Dear SGaist,

    Yes, I guessed it as you mentioned.
    I just want to know how to optimize directfb performance why I asked the question.

    Thanks for relpying it :)


  • Lifetime Qt Champion

    Can you give more details about your use case ?



  • @SGaist said in DirectFB performance:

    Can you give more details about your use case ?

    Hi SGaist,
    My issue is same with this, could you take a look at it? thansk!
    https://forum.qt.io/topic/81151/qt-directfb-performance-issue


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