I have started receiving app termination due to memory pressures very recently (mostly with iOS 7). The app used to work very well on iOS 6.
The app is mostly uses a UIWebView to display a webpage. However for a few webpages it creates ever increasing Dirty memory with most of it due to Image IO and Performance tool data (see attached instruments screenshots). I am completely clueless as to where to dig next. Could someone guide me what should I do here onwards? In the second screenshot I see a sudden bump in the memory allocations. Is there a way to spot the process/part of the code which caused it?
EDIT One can reproduce these results in a simple demo kept at www.github.com/nikhiljjoshi/iosCrash (just change the site to www.nzz.ch).
Thanks in advance,
Nikhil
Related
I am currently struggling with memory management inside a webgl application on the web, on iOS only.
I keep getting the following error message :
Application 'UIKitApplication:com.apple.Preferences[0xa7c1]' was killed by jetsam.
I understand that Jetsam is the system process responsible for memory management, but the crash occurs while the browser uses around 25% of the device's RAM, which is not that high. I don't have any other open application while running my webGL content. What I don't understand is what Taun Chapman said :
Jetsam monitors memory use and kills applications which are not good memory citizens. A good memory citizen is an application which is willing to give back memory when asked and does not keep asking for more memory.
Well, the app needs more memory in a short time (when unzipping 3D models using workers), I can't continue my app without it! And it crashed at these particular times.
Moreover, I think I have some memory leaks in my app, according to Chrome DevTools I am currently trying to fix. But the browser itself seems to have some leaks too. Thus, fixing mine will just delay the inevitable.
I know the following question is odd, or inappropriate, but do you know if the jetsam "limit" can be increased ? Or if you can add an exception on the currently running WebGL app ?
For your information, I use the Three.js WebGL library and the zip.js library to compress my 3D models.
Yes, I've already read the following question : Why does simple website crash on mobile (iOS Safari and Chrome, at least)?, but the problem does not come from my CSS.
The 10.3.2 version of iOS (released the 15th of May) made Jetsam less aggressive, or at least, the memory is better handled.
https://support.apple.com/en-gb/HT207798
I am writing a game in Swift using SpriteKit with Xcode 7.3 on a Mac mini running El Capitan (both updated in last couple of days).
Shortly after I started, my Mac mini started crashing. The error log indicated that a Kernel Panic had occurred likely due to a memory leak & the process was identified as Xcode. Looking at the Activity Monitor, I can see that when this specific app is loaded in Xcode, the memory used by Xcode fairly rapidly increases even though the App is just sitting there doing nothing.
When other apps are loaded & idle, the memory usage stays more or less constant as you would expect. I have Googled for clues for several hours but can find only info. about memory leaks when an App is running & how to detect them with Instruments.
This is a weird one as far as I'm concerned. I do not have any idea how to start to figure out what's causing this other than starting with a fresh project & gradually adding code to see if/where it starts happening again. I would appreciate any ideas other Xcode users may have.
You don't happen to have
skView.showPhysics = true
turned on?
That is know to be causing memory issues exactly as you described.
There are a number of things you can do to start diagnosing this issue. Firstly you say that only one app is doing this. So this would indicate that the problem is an app problem rather than XCode. This is a good thing :-)
Next I would start using the profiler to monitor the memory and allocated objects in the app. try taking snap shots of the memory at regular intervals and look at what has been allocated since the prior snap shot. The profiler can then help you to dig down into the leaking objects and see where they are being retained and released. This might give you the clue you need.
Another thing is try is the profilers leaks monitoring. That also might tell you whats going on inside your app.
Lastly, is there anything in your code that is executing in some sort of loop. Something that animates on the home screen for example. Perhaps that is leaking.
Thanks very much to Drekka & Adrian B for your speedy answers but, as always happens, as soon as I post a question, I stumble across some information that leads to an understanding & (in this case partial) solution. Looking for an answer to a different question, I came across a thread on the Apple Developers Forum where several others are reporting the same issue.
It is related to the use of the SpriteKit Scene Editor. Hence it is app related in that for me it occurred with the only app for which I have ever used the Scene Editor but in reality it is an Xcode bug. What happens is that if the Scene Editor window is open (i.e. the .sks file is selected), even if the scene is blank, Xcode starts to leak memory at a rate of about 1MB/sec. If you close that window, the leakage stops. It happens even if Xcode is minimized. Apparently, it has been reported as a bug. I guess the work around for now is to accept the leakage while you're modifying your scene & then close the editor when you've finished (or do everything in code).
Cheers,
RB
I am working on an iOS app in Xcode. Earlier I got it to start and run, up to a limited level of functionality. Then there were compilation failures claiming untouched boilerplate generated code had syntax errors. Copying the source code into a new project gets a different problem.
Right now, I can compile and start running, but it states before even the launch image shows up that the application was closed due to memory pressure. The total visual assets is around 272M, which could be optimized some without hurting graphical richness, and is so far the only area of the program expected to be large. (The assets may or may not be kept in memory; for instance every current loading image is populated and my code never accesses any loading image programmatically.) And it crashes before the loading image has itself loaded.
How can I address this memory issue? I may be able to slim down the way images are handled, but I suspect there is another root cause. Or is this excessive memory consumption?
Thanks,
Review the Performance Tuning section of Apple's iOS Programming documentation. Use Apple's Instruments application to determine how, when, and how much memory your app is using.
One approach you should consider is to disconnect the graphics resources from your application, and add them back one-by-one once you feel they meet the requirements and limitations of iOS.
Now, this part of my answer is opinion: it sounds like your app is a high risk for being rejected from the App Store, in case that is your intended destination for this app.
I am working on an iOS app in Xcode. Earlier I got it to start and run, up to a limited level of functionality. Then there were compilation failures claiming untouched boilerplate generated code had syntax errors. Copying the source code into a new project gets a different problem.
Right now, I can compile and start running, but it states before even the launch image shows up that the application was closed due to memory pressure. The total visual assets is around 272M, which could be optimized some without hurting graphical richness, and is so far the only area of the program expected to be large. (The assets may or may not be kept in memory; for instance every current loading image is populated and my code never accesses any loading image programmatically.) And it crashes before the loading image has itself loaded.
How can I address this memory issue? I may be able to slim down the way images are handled, but I suspect there is another root cause. Or is this excessive memory consumption?
Thanks,
Review the Performance Tuning section of Apple's iOS Programming documentation. Use Apple's Instruments application to determine how, when, and how much memory your app is using.
One approach you should consider is to disconnect the graphics resources from your application, and add them back one-by-one once you feel they meet the requirements and limitations of iOS.
Now, this part of my answer is opinion: it sounds like your app is a high risk for being rejected from the App Store, in case that is your intended destination for this app.
I’m helping out a company with a project for iOS, which is using Core Text. Some users of the app have reported that text is occasionally missing from within the app. It seems™ that this is somewhat memory related, because it’s solvable by shutting down the app along with background apps.
I made a few lines of code which simulates the use of the app – so the app “runs itself”, navigating between view controllers randomly, scrolling in text fields etc – to track if this issue occurs by normal use.
I’ve found some memory leaks related to the use of Core Text, but according to instruments the amount of memory lost is quite low. However, when the simulation has been running for about 20 minutes or so, the app is shut down by the os because of memory warnings.
I’m intending to fix this memory leaks, but my problem is that I will not be able to ensure that this fixes the main bug (missing text), since I cannot reproduce it myself.
So my final question is: have anyone experienced issues with missing text on iOS while using Core Text, which are due to leaked memory? Does it sound plausible? If so, is this related to only specific versions of iOS?
I appreciate any answers that can help me out!
UIViewControllers may implement didReceiveMemoryWarning that the system calls when your app is on low memory. Framework classes, as core text, are most likely do implement this and act accordingly to save memory. So it is possible that your core text object aims to help your app resolving the low-mem situation with freeing some of its resources that can even cause it to blank its contents. Fix first all memory leaks in your app.
On the other hand, all bugs are very difficult to correct if you can't reproduce them. If you suspect that the issue is due to low memory, try to simulate this yourself by allocating huge amount of memory in your application and hope that you can reproduce the erroneous behavior that way.