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Optimize QML Application on embedded device (Render Bind)



  • Hello everyone,
    I inherited a QT project which make uses of QT Quick and QML for embedded device.
    I will be short; the present situation and problem is the following:
    In some configurations the FPS on target are about 47-50 fps and that is ok.
    In other configurations the PFS on target drop to 30 fps and this is not ok.

    I configured the profiler and got some traces in both configurations.
    The main difference in the traces which I spotted is the "Render Bind" sub-item of "Scene Graph".
    Infact when my application run at 47-50 FPS the "Render Bind" is about 12 ms.
    When my application run at 30 FPS the the "Render Bind" is about 24 ms.
    The other elements of the profile trace seems more or less the same in both the configurations.

    I'm new to qml and the project was not written by me.
    How can I decrease the "Render Bind" time? On what should i focus?
    In the 30 FPS configurations are drawn more components on the screen. I will comment them for debug first but they are required so I will need to keep them.

    Unfortunately the (https://doc.qt.io/qtcreator/creator-qml-performance-monitor.html) page does not say a lot of word about "Render Bind".

    Any help? suggestion?

    I thanks you all in advance and, I repeat myself, I'm new to QML so I will not be offended if you are a little pedantic.


  • Lifetime Qt Champion

    @Andak Found this
    "Render Bind Render Threaded, Basic, Windows time in renderer ... binding Binding the correct framebuffer for OpenGL rendering. This is part of the gross Render step. May not be properly aligned with Render with versions of Qt prior to Qt 5.5."
    here https://doc.qt.io/qtcreator/creator-qml-performance-monitor.html
    Not sure it helps you.



  • Thanks @jsulm for your reply,
    unfortunately I already read that page (is the one I linked in my original post) but it does not help me to understand where I need to modify/optimize etc..


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