How to stop UIView from interrupting performSelector

Question

I have a method running performSelector on itself every .01 seconds in order to constantly update an image.

-(void)setNeeds

[mag setNeedsDisplay];
[vc setNeedsDisplay];
[na setNeedsDisplay];
[wave setNeedsDisplay];
[mon setNeedsDisplay];

[self performSelector:@selector(setNeeds)
           withObject:NULL
           afterDelay:.01];

This updates just fine when there is normal user interaction. However, when a user slides values around on the UIViewPicker, all updates are paused until the interaction stops. The same thing happens with an NSTimer object set on repeat.

I'm hoping for a more consistent method of performing a continuous action but a solution to this problem would also be grand.