How to interpret the output from the “Leaks” XCode performance tool?

Question

I don't understand the output from the "Leaks" performance tool in XCode. How can I interpret this output?

Answer 1

The Leaks Instrument looks for blocks of memory that are not referenced from the application code.

The Table View shows the addresses of the block found in such condition.

Yes, Instruments it's not simple to use, there are many leaks apparently from the OS and/or the system libraries, the details often show over-freed blocks (?!).

Life is complex :)

Answer 2

Leaks is only marginally useful. A much bigger problem you will have is references which are still retained that you think have been released. For that, use the Object Allocation tool with "created and still living" checked.

If you see memory use increase over time, highlight a region and see what objects are allocated in your own code that you were not expecting.

Answer 3

Leaks is covered in a wonderful video of Lecture 10 of Stanford's CS 193P (Cocoa/iPhone Application Programming).

http://www.stanford.edu/class/cs193p/cgi-bin/index.php