Question

I am working on an iPhone game which receives memory warning that I am not experienced enough to interpret. I have been watching some iTunesU tutorial but I am still not very good at this..

I have received various memory leaks whilst running my game and I wanted to understand how to interpret the stack trace show in Instruments properly.

I attach a screenshot of the ObjectAllocation instrument output . Even when I zoom filter I don’t manage to filter the data in the ObjectSummary .

The peaks in memory usage in 1 happen when the GameScene is initialized and all the data is loaded (ParallaxBackground, CCSpriteBatchNode) and Sprites and bullets frames are created (in an CCArray of spriteFrames).

The big blue peak is just at load time but the app freezes and then crashes only after a while and from the graph I see that the memory usage (blue bar) has gone down.. so I don’t quiet get that. Also, whenver I try to use the leaks instrument the App crashes..

I know is a very silly question for someone experienced, but I just need some extra help getting started with this toolset.

I think the memory problem are due to the sprites I allocate in sprite cache classes, but I am not sure on this and hence wanted to investigate this using Instruments but can’t find out how to see what is the object causing the memory warning and how to access the stack trace..

PS: I am running on an iPod 4th generatio and I am using Cocos2D as library

EDIT: I do not also understand why if the Live Bytes are only 1.01 MB the App crashes and why I still receive a memory warning (see black flags). Is it due to some pointer referencing to some null variable or due to an excessive memory allocation? 1.01 MB doesn’t seem much to me..

EDIT 2: Following Marion’s advice I used the Activity Monitor and realized that the effective real memory usage is 55.39 MB. I misinterpreted the “live bytes” word. I will try to dig into this further and will leave the question as unaccepted for now to allow other people contribute. If I won’t have any other answer within one-two days I’ll mark as accepted the current answer. Thanks!

Thanks a lot!

Answer 1

If you want to find leaks, use Leaks instrument instead of Allocations. To find out, how much memory use at the moment, use ActivityMonitor.

If you will have problems with memory in cocos2d, you can try to purge cache. In cocos2d you can purge CCTextureCache, CCSpriteFrameCache, CCAnimationCache. It will release unused textures and frames.

If you want to check if all of unnessesary textures were removed from memory, you can place breakpoint to CCTextureCache class and call, for example, sharedTextureCache and look throw the content of textures_ dictionary. Or add some method to this class to be able to dump current state of cache.