iPhone App启动时会占用大量内存

Question

If I put a breakpoint on my first line of code from main function, I see in the activity monitor 17MB of memory for my app. Do you have any idea why the memory usage is so high without anything loaded? (Maybe the OS is loading many things, but not me)

This memory usage has almost the same size as the app executable. Is the executable fully loaded at startup?
How can I reduce the initial memory size?

Answer 1

不要看活动监视器，而使用工具（配置文件，分配）。

Answer 2

I think the fact that it's the same size as your app bundle is probably just a coincidence because the whole bundle is not loaded into memory on startup.

As CocoaFu said, use the allocations tool to see how much memory your app is allocating. It will be much smaller than the activity monitor tool because it does not include memory used by OpenGL (which backs all user interface elements).

Most likely, you actual allocations are quite small (a MB or less) while the other 16 or so MB are all of the interface elements of your app being created by UIKit (ie your navigation controller, various view controllers, buttons, whatever). Note that on an iPhone 4 or iPod touch 4th gen, the OpenGL allocations (ie the difference between the allocations tool and activity monitor tool) will be roughly two to four times the size than on earlier models because the screen has 4 times the resolution so all UI elements are larger.