Mac OS X 10.10: Slow frame rate when moving window near the menu bar

Originator:jacob
Number:rdar://18305041 Date Originated:11-Sep-2014 09:10 AM
Status:Open Resolved:
Product:OS X Product Version:Mac OS X 10.10 (14A343f)
Classification:Performance Reproducible:Always
 
Summary:
Moving a window (by its titlebar for example) near the top of the screen by the menu bar drops the frame rate from about 45-50fps to about 20-25 on my hardware. Only happens when Reduce Transparency in Accessibility Settings is off (which is system default). With reduced transparency, the frames rate is close to 60fps. The jerkiness of the reduced frame rate is quite visible.

Steps to Reproduce:
1. Grab a window (such as Safari) but its title and move it around the screen. Approaching the menu bar closer than about 1.5 times its height will cause the window movement to be jerkier (may depend on hardware, mine is 2012 Retina MBP) but certainly drop the frame rate.

Expected Results:
Smooth movement in all locations on the screen

Actual Results:
Reduced frame rate

Regression:
With Reduce Transparency in Accessibility Settings enabled, this doesn’t occur

Notes:

Comments


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