title: iPhone + OpenGL + Touches: FPS drop
body: <p>Recently I ran into a very strange issue: touching the screen of the iPhone and moving a finger around can eat up to 50% of my FPS. Yeah, I checked my code for possible bottlenecks – not the issue. The last resort I tried before writing this post – commenting out all the touch processing code and looking at FPS then. Results are: no touches – 58-60. Touching and moving the finger – 35-40 FPS instantly.</p>
  
  <p>The rendering is done in a separate thread, so that no main runloop events shall collide with it. However, it's very crushial for me (and the game I develop) to resolve this issue, because such FPS drop is really noticeable.</p>
  
  <p>Thank you for your help in advance. </p>
  
  <p><strong>UPDATE</strong>: seems that setting rendering thread's priority to higher value helps a bit...</p>