QTimer restart increasing CPU usage

marcosbontempo

Hello,

I need to reset a QTimer every time the touchscreen of a display is pressed. I'm using this command to reset the timer:

timer->start(interval*1000*60);

But every time I touch the display the CPU usage of the programa increases. Does anybody know how to correct it? After some time using the program, the CPU usage gets 100%;

Any tip will be very helpful,
Thanks.

mrjj

hi
from one line of code its hard to give guesses.

Do you create a new timer each time you "touch" ?

The function that is called when timeout happens, what are you doing in there?`
Do you have loops ?

marcosbontempo

@mrjj

I use the same timer.

I don't have loops in the function that is called when timeout happens.

When I press the touchscreen, this function is executed:

void TimeControl::restartTimeCounter(int timeoutType)
{
    // Restart timer:
    int interval = qdbc->generalconfig->getConfigurationInt(CONFIGURATION_ATTRIBUTE_DISPLAY_IDLE_TIME);
    timer->stop();
    timer->start(interval*1000*60); // LINHA QUE CAUSA O AUMENTO DE CPU

    switch(timeoutType)
    {
        case 1: // Display control
            if(display == false)
            {
                display = true;
                turnOnDisplay();
            }
        break;
    }
}

This is the function that is called when timeout happens:

void TimeControl::turnOnDisplay()
{
    QFile backlight_file(backlight);

    int action = qdbc->generalconfig->getConfigurationInt(CONFIGURATION_ATTRIBUTE_DISPLAY_ACTION);

    if(display)
    {
        switch(action)
        {
            case PhotoFrame:
                // Stop photoframe
                qdbc->photoframe->stopPhotoframe();
            break;
            case Brightness:
                // Turn on display
                QString brightness = qdbc->generalconfig->getConfigurationString(CONFIGURATION_ATTRIBUTE_DISPLAY_BRIGHTNESS);
                if(backlight_file.open(QFile::WriteOnly | QFile::Truncate)){
                    backlight_file.reset();
                    QTextStream back(&backlight_file);
                    back << brightness;
                }
                backlight_file.close();
            break;
        }

        display = true;
    }
    else
    {
        switch(action)
        {
            case PhotoFrame:
                // Run Photoframe
                qdbc->photoframe->runPhotoframe();
            break;
            case Brightness:
                // Turn off display
                if(backlight_file.open(QFile::WriteOnly | QFile::Truncate)){
                    backlight_file.reset();
                    QTextStream back(&backlight_file);
                    back << "0";
                    qdbc->callreceived->closeGUI();
                }
                backlight_file.close();
            break;
            case MainPage:
                // Return to main page
                qdbc->callreceived->closeGUI();
            break;
        }

        display = false;
    }
}

mrjj

hmm.
It dont really look heavy.
I wonder if qdbc->photoframe->runPhotoframe();
could be the heavy one?

marcosbontempo

@mrjj

Thanks for your answer!

I commented all the content of the function that is called when timeout happens (turnOnDisplay). However, the CPU usage increasing still continues. The only line that is beeing called is

timer->start(interval*1000*60);

JKSH

What is your OS and your version of Qt?

What are the usual values of interval?