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iosobjective-cperformancecpunsdata

High CPU activity with `dataWithData` + non-blocking thread

I'm trying to fixe an issue that I can see on my iDevice but not on my Mac (obviously).

I've marked a very high CPU activity on this line:

data = [NSData dataWithData:UIImageJPEGRepresentation(image, 1.0)];

This appears when I'm downloading and showing a HD picture (4-5Mo).

Is anything wrong in my code or am I doing something really bad ?

Edit

Finally this line was not that important. My problem was that I thought that my asynchronous method was in another thread. It wasn't.

I start thinking about new thread with:

[NSThread detachNewThreadSelector:@selector(test:) toTarget:self withObject:myObject];

For my problem, is it the best way to do it ?

Solution

  • There is a solution here very well explain for the problem of non-blocking thread using NSManagedObjectContext with children.

    For the other problem( high CPU activity) is was due to this non-blocking thread problem.