title: Prioritize NSTimer
body: <p>I have an <code>NSTimer</code> running. The app is doing a lot of things concurrently with the <code>NSTimer</code> (including in the same view controller as well as the app delegate). I cannot figure out why, but sometimes the <code>NSTimer</code> pauses and does not update a label. (It acts as a stop watch of sorts for the user.)</p>
  
  <p>Should I try to figure this out using Instruments? To use global <code>dispatch_async()</code> for thing being called while it is being interrupted? Or is there a way to prioritize the NSTimer and the method it calls?</p>
  
  <p>I'm creating the timer like so:</p>
  
  <pre><code>oneSecondTicker = [NSTimer scheduledTimerWithTimeInterval:1.0 
                                                     target:self 
                                                   selector:@selector(updateLabelsWithOneSecondTicker) 
                                                   userInfo:nil
                                                    repeats:YES];
  
  [[NSRunLoop currentRunLoop] addTimer:oneSecondTicker forMode:UITrackingRunLoopMode]; //!important
  </code></pre>