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[problem found]Qt Creator slow on Mac v10.7 (Lion)



  • I upgraded my iMac from OS X v10.6 to v10.7 (Lion) and installed the XCode v4.1.1. After this upgrade, my Qt Creator is noticeably slow when I opened my project in designer. It takes several seconds to see a widget is selected after clicking on it. The CPU usage for Qt Creator in the "top" output is always >80% even the designer window is not selected. By comparison, I copied my project to my Mac laptop, which is still running Mac OS v10.6 with XCode v3. The Qt Creator only uses 2% CPU when opened the project and leave the designer window untouched.

    Any boy has similar experience? Any way to fix the problem?

    Thanks.



  • Just found a clue. The iMac's screen is much larger than my laptop. On the iMac the whole designer main window (1600x1000) is shown, which contains several hundred widgets. On the laptop, only partial main window (and less widgets) is shown. If I reduce the Qt Creator's window size on iMac to show only a part of the widgets in the designer, The CPU usage will drop. On laptop, if I scroll the designer window to show widgets concentrated area, the CPU usage will go up. Looks like showing more widgets will cause more CPU usage even the Qt Creator's window is not selected. Does Qt keep updating/painting the widgets?



  • Did you file a "bug report":http://bugreports.qt.nokia.com/ about the issue?



  • It is the progress bars in the GUI costing the CPU cycles whenever their values are between 0 and 100.
    Created a bug.



  • Can you post a link to the bug report?





  • Thanks! Always useful to have a reference to the bug on the thread.


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