Hey how can I analyze my apps memory usage more detailed in Xcode 4 like what things eat memory, as it seems my app takes god damn 40mb memory something is seriously wrong here. Any tools I can analyze my code with?
Choose Product / Profile or CMD-I. It runs your app in Instruments. Choose Leaks or Allocations to see how you memory is being used as the app runs.
Related
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.
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.
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.
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.
The Info
I recently launched an app on the AppStore. After testing on the simulator thousands of times, and actual devices hundreds of times we finally released our app.
The Problem
Reviews started popping up about app crashes when the user launches the app. We figured that the app crashes on launch on iOS devices with less than (or equal to) 256 Mb of RAM. The following devices are devices our app supports with less than 256:
iPod Touch 4G
iPhone 3GS
iPad 1
The app doesn't always crash. Sometimes it launches fine and runs smoothly. Other times it crashes. The time from launch (when the user taps the icon) to crash is usually two seconds, which would mean that the system isn't shutting it down.
Findings
When using Instruments to test on certain devices, I find the following:
There are no memory leaks (I'm using ARC), but there are memory warnings
Items are being allocated like crazy. There are so many allocated items, and even though I'm using ARC it's as if ARC isn't doing what it's supposed to be doing
Because of what I see as "over-allocation", the result is:
This app takes (on average) 60 MB of Real Memory and 166 MB of Virtual. When the app launches the memory being used quickly increases until it reaches about 60 MB at which point the view has been loaded.
Here is a snapshot of the Activity Monitor in Instruments:
I know that those figures are WAYY to high (although the CPU % never really gets up there). I am worried that ARC is not working properly, or the more likely case: I'm not allocating objects correctly. What could possibly be happening?
The Code and Warnings
In Xcode, there are only a few warnings, none of which pertain to the app launch or any files associated with the launching of the app. I placed breakpoints in both the App Delegate and my viewDidLoad method to check and see if the crash occurred there - it didn't.
More Background Info
Also, Xcode never generates any errors or messages in the debugger. There are also no crash reports in iTunes Connect, it just says, "Too few reports have been submitted for a report to be shown." I've added crash reporting to my app, but I haven't released that version.
A Few Questions
I started using Obj-C just as ARC arrived, so I'm new to dealing with memory, allocation, etc. (that is probably obvious) but I'd like to know a few things:
How can I use #autoreleasepool to reduce my memory impact? What do I do with memory warnings, what do I write in the didRecieveMemoryWarning since I'm using ARC?
Would removing NSLog statements help speed things up?
And the most important question:
Why does my app take up so much memory and how can I reduce my whopping 60 MB footprint?
I'd really appreciate any help! Thanks in advance!
EDIT: After testing on the iPhone 4 (A4), we noticed that the app doesn't crash when run whereas on devices with less than 256 MB of RAM it does.
I finally solved the issue. I spent a few hours pondering why my application could possibly take up more RAM than Angry Birds or Doodle Jump. That just didn't make sense, because my app does no CALayer Drawing, or complex Open GL Graphics Rendering, or heavy web connection.
I found this slideshow while searching for answers and slide 17 listed the ways to reduce memory footprint. One thing that stuck out was PNGCrush (Graphics Compression).
My app contains a lot of custom graphics (PNG files), but I hadn't thought of them affecting my app in any way, apparently images (when not optimized properly) severely increase an applications memory footprint.
After installing PNGCrush and using it on a particularly large image (3.2 MB) and then deleting a few unused images I ended up reducing my apps memory footprint from 60+ MB and severe lag to 35 MB and no lag. That took a whopping five minutes.
I haven't finished "crushing" all my images, but when I do I'll update everyone on the final memory footprint.
For all those interested, here is a link to a blog that explains how to install PNGCrush (it's rather complicated).
UPDATE: Instead of using the PNGCrush process (which is very helpful, although time consuming with lots of images) I now use a program called ImageOptim that provides a GUI for multiple scripts like PNGCrush. Heres a short description:
ImageOptim seamlessly integrates various optimisation tools: PNGOUT, AdvPNG, PNGCrush, extended OptiPNG, JpegOptim, jpegrescan, jpegtran, and Gifsicle.
Here's a link to the website with a free download for OS X 10.6 - 10.8. Note, I am not a developer, publisher or advertiser of this software.
I'm trying to debug a mysterious app crash that happens after running the app for a few hours.
My hunch is that this may be memory related, as I've not done any memory optimization since starting to build my app.
I'm looking at my application with the "allocations" instrument and I see these numbers:
All allocations 4.70mb
Living 51072
Transitory 357280
Overall Bytes 100.23mb
Overall 408000
Which is the important number here? Does my app take 4.7 Mb of memory or 100 Mb? At which point should I be concerned about my app being killed for memory reasons? I want to avoid premature optimization :)
Since I'm using ARC and TabBarController, most of the controller related memory seems to be out of my hands, unless I find out how to create a tab and lazily init a controller when that tab is first touched.
Thank you!
Hey, now when I finally got to test my app on a device it eats 40mb memory at the beginning which is a huge amount. Is there any good way to determine where exactly things went wrong?
Yes, use the memory allocations and leaks profilers that are part of the Instruments application.
You'll probably want to profile it using the Instruments app that comes with Xcode.
My app crashes after playing for more than 30 min on some screen due to low memory will my app get reject due to this?
actually i tried a lot to solve but it shows no trace in instrument i even did all permutation combination of code by commenting checking what causing the problem but i was not successful to solve it yet.
its an ipad application 3.2 sdk
I have notice many app which crash due to low memory and they are happily on app store
Any clues,suggestion ,advice will be appreciated.
Thanks in advance
Bill Bumgarner recently wrote up a blog post on using Heapshot Analysis to catch memory growth when some of the more traditional techniques fail. Although his write up is in the context of a Mac OS application, the technique should be equally applicable to iOS. Bill walks you through using the Allocations Instrument to do Heapshot Analysis and track down your leak.
Perhaps this technique will help you track down your memory issues.
See bbum's weblog-o-mat » Blog Archive » When is a Leak not a Leak? Using Heapshot Analysis to Find Undesirable Memory Growth