I have a UIViewController and I'm noticing that I've done something to where the didReceiveMemoryWarning method is getting called every time I run it on an actual device.
I've run the project with Run > Run With Performance Tool > Object Allocations (and Leaks also). There are no leaks but I have no idea how to read or understand the "Object Allocations" data that is displayed.
So ...
How do I read this information and what is/are the best ways to figure out (and resolve) why this is happening?
Thanks
EDIT:
I should mention that I also have a number of 3rd party libraries/code that I've included in my project (e.g. Three20, MGTwitterEngine, FTUtils, extThree20JSON and Twitter+OAuth). Could this be causing this??? Or at least contributing to the problem?
EDIT #2:
Don't know if this helps but I notice that this is happening either everytime that I present a UIImagePickerController modally -OR- after a take a picture using it.
* UPDATE *
Ran it again with the Object Alloc tool for several minutes and I don't see anymore than 4.75MB being allocated at any given moment. The app was running on a device and typically with 2.5 MB allocated on average.
Does this seem problematic to anyone??? Seems like its in an acceptable range insofar as I understand thing.
This may happen some time when your device have less memory free to use. Check your device free memory.
The problem had to do with UIImagePickerController ... and all is answered in this post: Received memory warning. Level=1 when showing a UIImagePickerController
Related
I created a test project to confirm my memory leaks:
Project file: https://dl.dropbox.com/u/3703182/PickerView.zip
Basically a UIPickerView is connected to a datasource via IB. When it's connected to a datasource, it leaks. If not, no leak. I need to use a UIPickerView for an imminent app that needs to be released ASAP, unfortunately it guarantees a crash every 2 hours because of the leak. How can I use the UIPickerView despite the memory leaks without crashing?
EDIT:
It only leaks on device, not in simulator.
That is not a leak. It's an allocation.
If it was a leak it would show a red spike in the second row.
The real test for a leak is presenting and dismissing several times over. If you can do that and show that the allocations keep rising then there is a leak. Not otherwise.
Adding my comments as answer,
Your app will not crash due to this leak since it is a very small leak caused by framework which you dont have to worry about. The screenshot shows that it is in terms of a few bytes. If your app is crashing every 2 hours, that means there is something else which is using a lot of memory. Please check if you are using anything else in your code which could cause this and update the question with your finding.
In allocation tool, make sure you are checking the live bytes section and check how much it is going up. If it stays below 15-20 MB, you dont have to worry much anyways. Check this for more details about memory usage in app. Also check this XCode Instruments Allocations: Look at Live Bytes or Overall Bytes?.
This is the Apple library that is leaking. You cannot do anything about this. It is Apple's fault.
This isn't a leak you can control, it's internal... but this is a very small amount of memory and will not crash your application. I'd be interested in seeing what this looks like an hour in... Can you provide a backtrace of the crash? That would probably better help determine the real cause of the crash.
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!
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.
In my app user can take as may picture from camera, so after three time taking the picture it crashed. I can't resize the image (its requirement). So is there any other way to avoid memory leak.
Thanks
There is a know issue with the uiimagepickercontroller with memory leaks.
Apple recommend that you only allocate and instantiate only one instance and store it somewhere for the life of the application (whilst running that is).
Don't create a new one, use it and deallocate it each time you want to
use the control. If you do, your memory usage will keep increasing
until it crashes your app.
Personally I store it as a property in the appDelegate, but there may be a better way of doing it.
Edited: Thanks to CharlieMezak. Yes, such a leak might cause a crash. You'd better do some checking based on CharlieMezak's suggestions.
What may also cause crash is your code trying to access a piece of memory that was deallocated already.
I suggest you first check your code to see if there is any autorelease object that was not taken care of.
Second, turn on NSZombieEnabled, and test your app. If it's indeed trying to access something that was already deallocated (Zombie), the console will show you.
Third, and most importantly, post your crash report and part of the code that might be responsible for such a crash. Your description is somewhat vague, we need to see the report.
It sounds like your app is able to handle the photos correctly (from the user's perspective) two times, but on the third time it crashes. Sounds to me like a memory leak.
If it were a logical error in the code, or an attempt to access a deallocated object, the crash would probably occur the first time you take a photo.
It sounds like you're leaving the images in memory, so by the time you take your third photo, you're out of memory because the first two are still sitting there. Make sure you're releasing what you retain, and if you continue to have trouble, post your code!
I have an app that has a tabBar Controller and a navBar Controller. It has ~8 views (a variety of web, table, standard, mail, address etc.), some created using IB some created using XCode to make the table views. I've ran the memory leak tester and it doesn't have memory leaks. It can crash at anytime on any of the views, If I flip back and forth between views and use some of the functions it closes the app.
I assume that either I am running 1) out of memory or 2) not releasing views correctly, which causes the app to close. The app is simple so I don't know how I could be out of memory and I've reviewed the code to the best of my ability for releasing the objects correctly.
So Here is my list of questions:
1) What and How to use some of the other debugging tools (or tell me what tools/files I should be looking for using)? I would like to narrow down the problem to its source.
2) What is the best practice for releasing these views? How?
3) How much memory do normal apps use? Is there a number that I should stay around? How do I verify that in the simulator? the Allocation tool?
Feel free to point me to apple docs or other stackoverflow questions that can help me.
UPDATE: It appears to only be crashing one view is used, which has a table view with custom cells... The cell are populated from a plist file... this view worked fine a few days ago, I notice that some cells do not have data from the plist file... it could be a plist file problem with not storing proper data. I'll continue to work on it.
UPDATE #2: I went back to older rev of my files, to when this particular tableView worked just fine (pre 3.0) and guess what it works just fine, I change the simulator to 3.0 with this rev of the app and bam crash on this tableView shows up. Thanks for the help so far, I'll try somethings mentioned below and let you know what I find. If you have some tips on why a tableView w/custom cells from 2.2.1 to 3.0 would start crashing, I'll take them. If I can't get anywhere I'll post the code soon. BTW, I mis-spoke above, I thought it wasn't crashing in the simulator... I was wrong it is.
Solution: thanks for the troubleshooting tips the fix was quite simple, but it's odd it didn't crash in 2.2.1... it should have crashed a long time ago for the problem, I was releasing an object one to many times in my custom cell... duh.
On the first and second generation phone's you really don't want to be going over about 20 megs of real memory usage - once you get over that you are at risk of being killed by springboard.
One of the big culprits I've seen is autoreleased memory, since the autorelease pool can hold onto memory a lot longer than you would really like - if you are using a lot of autoreleased objects that can be a potential problem. You can improve this by doing more explicit retain/release where possible and by creating local autorelease pools manually and releasing them after doing a more intensive operation with a lot of autoreleased objects.
The most effective way to keep track of real memory usage I've found so far is running a debug build on a test phone and running with Activity Monitor. That will give you a clear idea of how much memory is getting taken and held onto by your app. As well as how much is being used when it crashes on you.
You can run with Activity Monitor in Xcode on the Run menu -> Start With Performance Tool -> Activity Monitor.
One other very useful tool is the CLang Static Analyzer that you can run against your code base and can give some very helpful memory management information. As mentioned here.
One thing I would try is putting some debug messages into your didReceiveMemoryWarning method(s). That way, if you are running out of memory, you'll at least have some warning.
I'm using the Leaks Instruments feature through Xcode to (try and) find memory leaks. I still haven't figured out how to use this program. I click Leaks in the program and see memory increasing as I do various things in the simulator. I have Extended Detail pane displayed. The only thing in Extended Detail pane that references my app is main. As in the main method produced by Xcode. Everything else is UIKit, Foundations, and other SDK classes I didn't write. What am I doing wrong that nothing is showing up from my app?
Before I hit 3 minutes, there are over 100 leaks totaling 2.5k. Is this common?
I've written up a Tutorial on using Instruments to track iPhone memory leaks. I'm not sure if it will help you with what you're dealing with or not...couldn't hurt, though. :-)
http://www.streamingcolour.com/blog/tutorials/tracking-iphone-memory-leaks/
Change the view to "Extended Detail" on the instruments panel. This will show you the stack trace of each leaked object after you stop recording and select the leaked object.
You do see calls into the API, but what you are interested in is finding the last method of your application before the API calls, that is where the leak is.
A tip: turn on "gather memory contents" in the leaks view. Seeing the object values should also help finding where the problem is.
You don't want any leaks. 100 leaks is not typical (at least in my apps ;) Typical should be 0.
I'm not familiar with how to use Leaks, but you can always try running the Clang analyzer on your code to see if that'll turn anything up: http://clang.llvm.org/StaticAnalysis.html. It can often find many bugs that might lead to memory leaks.
Xcode: run -> Start with Performance Tool -> Leaks
Keep in mind that the Simulator may leak when the device will not. Ran into that once already with UITableViewController class.
Use LLVM/Clang Static Analyzer.
Note also that the leak tool is not going to show you instances where objects are over-retained and still held on to. Leaks are cases where objects that should have been let go are just hanging around with no-one to clean them up. Over retained objects are validly held onto even though you'd think they should be gone - thus the leak tool cannot point them out, since they are still referred to and there's no way to tell them apart from objects that should still be retained.
To find those, use the memory reporting tool and make sure that memory use goes down fully after you free an object. If you notice something isn't freeing memory, you can start by putting breakpoints in dealloc to see if what you expect to see released is actually getting released.
You need to look for both cases to keep a clean memory footprint.
Run -> Start with Performance Tool -> Leaks
To detect memory leaks you can use the "build and analyze" function of Xcode.
Simply select Build -> Build and Analyze in the Xcode menu.
Made a sum up of the main memory leak tools: http://bcaccinolo.wordpress.com/2010/09/15/iphone-essential-performance-tools-list/
Leaks application that can be found in Xcode: run -> Start with Performance Tool -> Leaks.
Apple’s Instruments utility that can be found in /Developer/Applications/Performance Tools.
One of the best way to find the memory leaks is Select Product-> Analyze. In the left Xcode shows in which file you have memory leaks. What are the variable causing memory leaks. This is one of the best way to find memory leaks.
The memory debugger (button just over the console, next to the view debugger) is quite useful too.
It will show you leaks, and you can check /filter easily if objects are still in memory when they shouldn't.