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Thread: QTimer at 50Hz on Linux - High CPU Usage

  1. #1
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    Default QTimer at 50Hz on Linux - High CPU Usage

    Hello,
    I am using QT 5.8

    On Windows I have no ploblems.
    On Fedora 25 Using a qTimer set at 50 hz, the CPU usage rises to 90%.
    If I reduce the frequency of the qTimer the CPU usage decreases considerably.

    Qt Code:
    1. QTimer* m_timer; // in file .h
    2.  
    3. // in file .cpp
    4.  
    5. m_timer= new QTimer();
    6. int interval = (1 / 50) * 1000;
    7.  
    8. m_timer->start(interval);
    9.  
    10. connect(m_timer SIGNAL(timeout()),
    11. this, SLOT(slotRead()));
    To copy to clipboard, switch view to plain text mode 

    Can you give me some suggestions?

    Thanks in advance!
    Best Regards!

  2. #2
    Join Date
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    Default Re: QTimer at 50Hz on Linux - High CPU Usage

    Quote Originally Posted by Elisabetta View Post
    Qt Code:
    1. int interval = (1 / 50) * 1000;
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    Hi, "interval" here becomes zero because 1/50 is done using integers. This is probably not what you want (or not what you actually do...).

    Ginsengelf

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