View Full Version : Qt application runs slowly on RaspberryPi

10th July 2014, 09:37

I have finish my Qt application
I'm using a raspberryPi as device

The application consists on displaying data in a window
I have a start button, Stop button, Reset and Exit

I see that the application runs slowly, for example when I click on the stop button, I will wait a few secondes for stoping the display
Other problem : I display my data on real time, so I will see the changement of data but its not the case, I see the changement each few seconds

What do you think about the problem ?

Thank you

11th July 2014, 19:00
I think the problem is that you're asking your Pi to do too much work and it can't keep up. If you are plotting data in real time, there is probably so much painting stuff in the event queue that it takes the Pi a few seconds to get through it all before it can handle your click event.

15th July 2014, 18:35
I display my data on real time
I think it would be enough to update the display for example 25 times per second (each 40 ms).

1st August 2014, 11:13
Thank you

1st August 2014, 11:52
1. Are you using eglfs platform plugin and running your application without X11?
2. RaspberryPi has a powerfull GPU and slow CPU with only one core, so it would be good to move as much as you can to OpenGL. You can check "GForce recursive shaders" example on http://quitcoding.com/?page=work - they are showing history graph based on sensors.