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  4. CPU Load with Qt Quick much higher than with Qt Widget

CPU Load with Qt Quick much higher than with Qt Widget

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  • S Offline
    S Offline
    Snoopy
    wrote on last edited by
    #1

    Hello,

    On my embedded system with Linux Kernel OS I've tested a Qt Quick Application and a Qt Widget Application. Both only with one Window. Moving only the mouse with a normal speed there is a very big difference for CPU load.

    For Qt Quick it's much higher than for Qt Widget. It can be 21 % vs. 7 %.

    Has somebody an idea what's the cause could be ? Is there another mechanism for rendering the mouse cursor ? I don' t know..

    Thanks.

    Best regards

    snoopy

    A 1 Reply Last reply
    0
    • S Snoopy

      Hello,

      On my embedded system with Linux Kernel OS I've tested a Qt Quick Application and a Qt Widget Application. Both only with one Window. Moving only the mouse with a normal speed there is a very big difference for CPU load.

      For Qt Quick it's much higher than for Qt Widget. It can be 21 % vs. 7 %.

      Has somebody an idea what's the cause could be ? Is there another mechanism for rendering the mouse cursor ? I don' t know..

      Thanks.

      Best regards

      snoopy

      A Offline
      A Offline
      ambershark
      wrote on last edited by
      #2

      @Snoopy That doesn't surprise me much. QML is doing a lot more under the scenes than a C++ Widget would do.

      It could also be something you're doing in your QML. Here is a nice write up on QML performance and how to optimize your controls:

      http://doc.qt.io/qt-5/qtquick-performance.html

      My L-GPL'd C++ Logger github.com/ambershark-mike/sharklog

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      • S Offline
        S Offline
        Snoopy
        wrote on last edited by
        #3

        @ambershark okay. Thanks for the info.
        But one more question because we want to use Qt Quick:
        Would be CPU load for touch gesture the same how it is for using the mouse ? Or is that another mechansim again ?
        At the moment we can't test this because the display with touch we will get later.

        Best regards

        snoopy

        A 1 Reply Last reply
        0
        • S Snoopy

          @ambershark okay. Thanks for the info.
          But one more question because we want to use Qt Quick:
          Would be CPU load for touch gesture the same how it is for using the mouse ? Or is that another mechansim again ?
          At the moment we can't test this because the display with touch we will get later.

          Best regards

          snoopy

          A Offline
          A Offline
          ambershark
          wrote on last edited by
          #4

          @Snoopy I'm not sure. It would be easy to test, but I don't have the setup necessary for a quick test.

          My guess is that it will not do that on a touch device, but I could be wrong. It could be flooding signals or something "onMouseDown" that is causing it. Which could be something that happens with "onFingerDown" or similar.

          My L-GPL'd C++ Logger github.com/ambershark-mike/sharklog

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