why did Ubuntu turn off kernel preemption in Edgy?

[Phillip Susi]

Jan Claeys wrote:
> Considering that a human brain can unconsciously detect the difference
> between 65 Hz (flickers for most people) & 75 Hz (doesn't flicker for
> most people) CRT screen refresh rate, why wouldn't it be able to

That isn't because the brain can detect the flicker of the screen, it is 
because the flicker of the screen causes a beat with the flicker of the 
incandescent light bulbs in the room which are flickering at 60 Hz. 
When the screen is refreshing at 65 Hz and the lights are flickering at 
60 Hz, you get a 5 Hz beat which is quite noticeable.  Conventional 
televisions operate on the principal that the brain perceives only 29 
images per second as a continuous flowing scene.