Re: Operations Beachball
Re: Operations Beachball
- Subject: Re: Operations Beachball
- From: Charles Srstka <email@hidden>
- Date: Tue, 04 Dec 2012 12:40:13 -0600
On Dec 4, 2012, at 4:29 AM, Gerriet M. Denkmann <email@hidden> wrote:
> My app creates lots of MyOperations (subclass of NSOperation) and puts them into an NSOperationQueue.
>
> I would expect that the app thus remains responsive, but sometimes it is not.
>
> A sure way to beach-ball my app is: start it with a few hundred operations (which will take about 20 seconds to finish).
> Make some other app active.
> Try to make my app active again - it's panel stays grey and after a few seconds the cursor will turn into a beach-ball.
>
> These MyOperations interact with their controller in two ways:
>
> 1. they do once at start: [ controller dataStringFor: row ];
>
> The controller has:
>
> - (NSString *) dataStringFor: (NSUInteger)row
> {
> @synchronized(self)
> {
> if ( self.stringArray == nil ) { create it - takes some time, but happens only once};
> }
> return self.stringArray[row];
> }
>
>
> 2. When MyOperations have finished their work they call: [ controller done: row result: someNumber ];
>
> The controller has:
>
> - (void) done: (NSUInteger) row result: (NSUInteger) someNumber
> {
> @synchronized(self)
> {
> [ self.rowsToDo removeIndex: row ]; // NSMutableIndexSet
> };
>
> // sometimes do some logging, update user interface - but only every few seconds
> }
>
> So, why the beach-ball? What am I doing wrong? How to debug this? Why does the app-switch make the beach-ball appear?
I don't know that this will make a big difference, but since you're dealing with a performance issue, @synchronized is known to be much slower than other methods of synchronization. You could try replacing this with dispatch_sync on a serial queue, a spin lock, or a mutex and see if it helps at all.
Charles
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