CODEWITHSUNDEEP
iosmemory-managementautomatic-ref-counting
Genhain
Genhain

Reputation: 1937

iOS Memory malady madness

I recently ported a project over to ARC as I was having trouble with crashes and actually determining the cause, whether it was leaks or retain cycles etc., Now I have ported it over, I have not done massive testing to see whether it still crashes as I have not managed to get passed the activity monitor giving me the heeby jeebies when it shows my application doing This (activity monitor profiler)

activity monitor

whereas in allocations tools it looks something like

allocations

That real memory usage is not even the worst of it, at one point it shot up to around 90 odd MBs, I am unsure on how to proceed as I am not 100 percent sure what to do with the information given here, Except assume that I might be dong something, very wrong, And I have also run the leaks instrument, I have a few but they are minimal, they are all in bytes.

Does anyone have an explanation? or at the very least are able to clarify what I am possibly looking at? what's the difference between real memory usage and live bytes and overall bytes? Also these results were gotten doing exactly the same actions once and then showing you at the end of it.

I have been trying to reduce the real memory usage as pre ARC conversion I was having memory warnings and silent crashes frequently, I have not run into these again after converting, but I have not done any prolonged testing as I cannot conceive of even trying when the real memory usage looks like that. Which actually looks a lot higher than before ARC...Although the live bytes does look lower post ARC...Madness!

Upvotes: 0

Views: 85

Answers (1)

emrys57
emrys57

Reputation: 6806

Something that confused me for a while is that ARC - wonderful as it is - does not necessarily avoid the need for @autoreleasepool.

https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/MemoryMgmt/Articles/mmAutoreleasePools.html

I ran very large memory usage in an app until someone suggested:

@autoreleasepool {

    // lots of allocating of objects returned from methods then discarded

} // and the closing brace of the autoreleasepool block causes their memory to be recovered here

Maybe that will help you.

A good explanation of the meaning of the various columns in the profiler is at Instruments ObjectAlloc: Explanation of Live Bytes & Overall Bytes

Upvotes: 1

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