Memory graph / chart in XCode 5 during Debug

Question

What does "Memory" usage chart/graph exactly represents in XCode 5 Debug navigator window?

I have an iOS app project with ARC disabled and no-storyboard/xib (i.e. old style). All memory management done manually using retain/release/autorelease.

When I debug the project in XCode 5, the memory pie-chart / graph show gradually increasing memory usage as the app runs, exceeds 1 GB memory footprints within half hour.

Roughly, it keeps increasing by 0.1 to 0.3 MB per 2 to 3 second with very rare memory dips/decrease (of magnitude < 0.1 MB per 30 seconds).

Is this a concern (memory leak) with respect to memory management? I did memory analysis (using Allocations/Memory Leak through Instruments on XCode 4.6) but didn't find any leaks.

Answer 1

I am seeing an issue where memory (heap) grows indefinitely on heavy processing but when running the exact same binary without Xcode; memory usage is fine. Remember to test outside of Xcode -- no idea what the cause is. NSZombies and all other debug options are off.

Answer 2

It simply measures the memory your app uses. So if it is increasing it must be a memory leak.

When using the leak analysis tools, I would use it as a guideline. It may help you find leaks but with all automated tools it may not find it all. As certain pieces of code (Especially the more dynamic pieces) may be hard to predict what they do memory wise for an automated tool.

Answer 3

Found answer myself. Unfortunately I had NSZombieEnabled (Zombie object) for debug mode - see below - (menu Product > Scheme > Edit Scheme)

Typically NSZombieEnabled tool keeps even the released objects in memory to help developer find over released objects. Refer this link - What is NSZombie?

After I unchecked "Enable Zombie Objects" option, the memory usage stabilized to about 10 mb (not always increasing) even after half hour app usage - see below -

BOTTOM LINE - Ensure to clear "Enable Zombie Objects" when you want to analyze memory usage.