I'm figuring out memory issues with an iPad app using instruments - looking at the overall allocated bytes. My NSTimer causes the bytes to constantly increase, while commenting it out causes memory usage to remain static.
From viewDidLoad of my view controller:
tickTime = 1.0 / 30.0;
tickTimer = [NSTimer scheduledTimerWithTimeInterval:tickTime target: self selector:@selector(update2) userInfo: nil repeats: YES];
And the method update2:
- (void) update2 {
}
As you can see there is nothing done in the method whatsoever - yet the memory usage of the app constantly grows. If I comment out the line where I setup the timer, the memory usage remains the same.
Is this a bug in the iOS SDK? Does anyone know a workaround?
It's a pebkac issue - I was studying the "Overall Bytes" in Instruments, which is a measure of all memory the app has ever used, rather than a measure of current memory usage.
I'm still curious how to measure the app's current total memory usage - as "Live Bytes" is around 1.5mb - even with at least 20mb of .pngs loaded.
Does memory use drop if you do something via the UI? I.e. if you tap a button or something?
What objects are hanging about that shouldn't? Instruments gives a lot more information than just that your heap is growing.
In general, having a timer that ticks at 1/30th of a second interval is to be avoided.
if it is on the main thread, it'll make your app's responsiveness very choppy (at best) or totally unresponsive
if you are trying to do animation, use Core Animation (or one of the various Open GL patterns)
it'll eat battery life.
I believe that the timer may be "firing" to fast for the iPhone to process. I had this same problem and had to slow the timer down.
