I'm trying to get memory utilization data at runtime and I can't seem to find anything that corresponds to the readings available in the xCode profiler - http://imgur.com/ZPEswIe. Are these available at runtime? I've tried using mach_port_t data, inspecting active_count, inactive_count, wire_count, and free_count, but nothing seems to be adding up correctly. I've ensured that I'm properly converting page count to megabytes.
Thanks
Instruments would provide you much more in-depth information about your app. From your screenshot press Profile in Instruments
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I'm trying to debug why our SceneKit-based app is using so much memory but Xcode and Instruments / Allocations seem to have very different values for the amount of memory being used. When I look in Xcode I see something like 600 MB but when I transfer the same running session over to Instruments / Allocations, I see a very different number for persistent bytes, like 150 MB.
Which one is correct? Why the difference? Are they measuring different things?
(Regardless of whether I Transfer an Xcode debug session or start fresh in Instruments, it doesn't seem to make much difference.)
The reason that I care is that iOS is killing the app for excessive memory use (according to Xcode) but I can't seem to find the problem via Instruments.
I've tried turning off all GPU and Metal debug options but they don't seem to make a difference.
Which one is correct?
My intuition is: Instruments. It uses Dtrace to (sorry) instrument your code and watch actual allocations and deallocations as they happen, at the expense of performance. The Xcode debug navigator memory graph is more of an outside view designed to give a very general sense of what’s happening. That is exactly why the latter offers you a way to switch to the former — because that (Instruments) is where you’re going to get real measurements.
(However, let’s keep in mind that Instruments may fail to include in the total you’re seeing some virtual memory backing stores for graphics. There are plenty of WWDC videos discussing this topic in more detail. )
I know that this answer is quite late, but for the sake of future developers with the same problem, I would advise you to check the images in your assets folder. If any of your images have dimensions larger than 1000 x 1000 you should scale them down. With the example above, the image comprises of 1000000 pixels. Following how images are loading in (4 bytes per pixel), this means 4 MB of memory is used to load the image. Unbeknownst to me, I had an image of roughly 3600 * 4000 in my assets folder. Doing the maths, this was over 50 MB of memory usage!
I am having trouble in getting memory usage of a particular iOS application . Also i want to make sure that what ever output result i am getting is for particular running app on iPhone.
Please check the answer on this thread,
https://stackoverflow.com/a/787535/4030948
here is the way to get used memory bytes for your app.
And for the CPU usage of your application,
please check the answer on this thread,
https://stackoverflow.com/a/8382889/4030948
The quickest way is to select the 6th icon along, on the left panel in XCode.
Make sure you have selected to run your project on the iphone device you are looking for, and keep an eye on these usage monitors as you use the app. A more thorough analysis is available using Instruments, but this is the quickest way.
After getting numerous memory warnings in the console , I tried using the memory profile tool to understand the root cause. But I don't see any strange behavior in memory allocations.
Is there a way to know what exactly is causing the warning?
Edit:
Print screen of profiler
Thanks for any guidance
sorted By "Overall Bytes" and "Created and Still living"
and added some detail to that:
and the code detail:
There is no single reason for memory warning. First of all you should always profile on real device - never simulator.
Add a profiler gadget called "leaks" to search for memory leaks on profiler while doing profiling.
You can get memory warning depending on a device even at around 10 - 12MB used by your application. Unfortunately there is no official information from Apple how much you can safely use.
In profile check also Total Living bytes. Try optimizing your code with autoreleasepools (if you are doing lot's of object allocation in "for" loops for example.
You can also check in Profile which objects takes most space.
Without real project to play with - it will be really hard to point a problem. Depending if it's a game and how much images you're using - problem may be different.
as the title says, I have an app which works on iPad 2, but crashes on iPad 3. when running it the console gives me a low memory warning message. When the crash happens I symbolicate it, but there's really nothing that I can relate to the code, like it shows
process name, UUID, rpages, recent_max, [reason] (state)
and under those column headers just hexadecimal stuff, nothing showing method calls or lines in the project.
Any ideas? am I missing some flags in the code that allows for a better crash log?
Thanks.
If you're getting low memory warnings and fail to release enough memory to resolve the issue, your app will almost certainly crash. The thing is, I don't think that the particulars of how or why it crashed can possibly be illuminating. At that point, you're evaluating secondary symptoms. You really need to go back and figure out why you got the low memory warning in the first place and fix that problem.
As Daniel said, you can look at Technical Note 2151, but as it says:
When you see a low memory crash, rather than be concerned about what part of your code was executing at the time of termination, you should investigate your memory usage patterns and your responses to low memory warnings. Memory Allocations Help lists detailed steps on how to use the Leaks Instrument to discover memory leaks, and how to use the Allocations Instrument's Mark Heap feature to avoid abandoned memory. Memory Usage Performance Guidelines discusses the proper ways to respond to low-memory notifications as well as many tips for using memory effectively. It is also recommended that you check out the WWDC 2010 session, Advanced Memory Analysis with Instruments.
So, a couple of thoughts:
Have you looked for leaks? The Finding Leaks article walks you through how to use instruments to find your leaks.
If you turned on zombies, have you turned them off? Zombies is a great diagnostic tool, but just consumes memory.
Have you run your code through the static analyzer (shift+command+B or select "Analyze" on the "Product" menu)? Especially if using non-ARC code, this can find lots of memory issues.
Have you examined your allocations for unexplained increases without offsetting decreases with the Instrument's Allocations tool. Using that, you can run the program, look at the consumption of memory on the graph and see if you see any increases that aren't offset at some point by the corresponding decreases. And if so, highlight those increases in the graph:
For example, when running the Allocations tool, hold down the option key and then click-and-drag with your mouse to highlight a portion of the timeline, to identify what you want to inspect. You probably want to focus on one of your spikes in allocations. For example, I found a bump in my allocations and highlighted it as such (this was a ludicrously simple example where I create a huge array in viewDidLoad, but hopefully it give you the idea):
Note, I find it useful to show the call tree in the lower panel, it's often useful to select "Hide System Libraries", to focus on your code (and "Invert Call Tree", too). And if you double click on the method name in Instruments (in my example, here, it would be viewDidLoad), Instruments will then show you your code that's doing the allocation:
Low memory warnings generate a different kind of log than standard crashes. Take a look at the "Understanding Low Memory Reports" section of this article to understand what happened with your application and how you can debug it using Instruments: http://developer.apple.com/library/ios/#technotes/tn2151/_index.html
I've just been analyzing an ipad app I'm developing using Instruments. In particular I was interested in the memory usage, as I have been receiving some memory warnings.
First of all the Activity monitor reports overall some 40MB of memory used just after starting the application. This really seams like a lot to me. Especially as after the startup nothing really fancy is going on.
So I have been analyzing the app in the VM tracker.
First of all can somebody explain how to interpret the dirty memory? I mean the ipad doesn't really have virtual memory, in the sense that there is no swapping etc.
Ok the really weird thing is that I have some 40 MB of dirty memory, that is resident! Some 38MB are listed under IOKit. Under IOKit there is no further information, what that actually means.
So what exactly does IOKit do?
What could be causing this insane those huge values?
Any kind of hint is appreciated! :)
Try Heapshot Analysis, bbum has a great tutorial here.
Basically you take a Heapshot, run some procedure, take another Heapshot for several iterations. This will help find memory that lost but not a leak. I use this method often,
I have used Heapshot many times to great advantage, many thanks to bum.
What is dirty memory?
According to this session.
memory written by an app
all heap allocations
decoded image buffers
VM profile shows some info of the dirty memory
like dirty memory size. They are anonymous.
vmmap --summary App.memgraph
In this session, this Apple dev uses heap to get more info about the object sizes.
heap App.memgraph