Memory leak snapshot with no "Hide system libraries selected"-
Memory leak snapshot with "Hide system libraries selected"-
Do I need to worry for these leaks as after many memory cycles I have come up to this point wherein I do not find a memory leak source in my application.
Is my understanding OK ?
And this image shows memory leak in cycles and roots mode -
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I have an app that used a lot CoreGraphics and by using "UIGraphicsGetCurrentContext()" and "CGContextDrawImage" and etc CoreGraphics founctions, these functions call mmap() and these use a lot virtual memory.
The problem is when I receive low memory warning, the memory used by mmap() in virtual memory will not release automaticly, and I don't have a way to manually release them. The app crash due to the virtual memory pressure, my real RAM usage is very low. How can I manually release the mmap() memory created by CoreGraphics? Thx
Any idea why my app's memory usage does not increase whilst using Instruments profiler (searching for leaks), but does when I don't use any profiler? To the tune of 1MB per operation performed. Instruments does not show any leaks.
OS memory management is a complex thing. It is likely that when you free memory it is not returned immediately to the system, but instead it is still "attached" to your process to make any future allocations your application needs more efficient. Although it is recorded as part of your process's memory space, it would be marked as unused, and when the system is running out of memory (or when your application exits), it would then reclaim the unused memory from your application.
If Instruments isn't reporting any leaks, you should be fine.
I followed this video tutorial for detecting memory leaks using Instruments with Xcode 4.3.2.
As you can see from the video, the creator gets a lot of useful feedback on the type of object that was leaked etc.
When I run instruments, I detect a few memory leaks but don't get much useful feedback on them:
What does it mean "Root Leaks"? Why is there no more useful information like in the screen above?
Is this something I can fix?
I'm using ARC within my app - does that effect Instruments finding memory leaks in any way?
A root leak can be one of two things. It can be a single memory leak, or it can be the start of a leak cycle. A leak cycle occurs when you lose a reference to a group of objects. A memory leak leaks one object while a leak cycle leaks a group of objects.
Your code may not have any leak cycles, which would explain why your Cycles and Roots section shows less information than the tutorial. Choosing Call Tree instead of Cycles and Roots from the jump bar can help you find the areas of your code that are leaking memory.
I have an application which allocates a large number of objects (mostly of 3 classes) and occasionally releases these.
The ActivityMonitor Real Memory Usage only ever goes up, never down. (Indeed I have noticed this with other applications.)
Profiling shows my application has no leaks, and Garbage Collections shows objects being reclaimed.
I'm sure it's a memory leak, and I'm certainly no expert in memory allocation, but instruments says I have a memory leak of zero bytes...
Can someone explain what exactly that means?
The leaked object (including the responsible party that initiates it) should appear in the lower half part of the Instruments window, once you have selected the "Leaks Discovered".
Doing an "Analyze" (Command + I) in XCode will also show possible memory leaks in your code.