title: How to diagnose an unexpected delay during dragging?
body: <p>From time to time, one of my apps experiences a delay of 2-10sec whilst dragging an object in a complex view. In some cases, the delay is sufficient to cause the wait cursor (spinning pizza of death) to appear.</p>
  
  <p>Time Profiler reveals nothing very remarkable -- just the expected drawing calls to update the view as the object is dragged. (This is a lot of computation, but I see no obvious difference in the profile during pauses and between pauses.)</p>
  
  <p>Memory profiler reveals nothing special about the pauses. Allocation seems flat throughout the drag. Leaks is clean.  (My initial assumption was that I was spinning off too many autoreleased objects, but that doesn't seem to be the issue.)</p>
  
  <p>Activity Monitor indicates that during the drag I'm pretty much using up one core for all the redrawing. That's what I expect.</p>
  
  <p>Any ideas of where to look next?</p>