I am having some trouble around memory leaks in my app.
I just wanted to know that whether it is possible to identify how much memory allocated by my app on heap so that i can reduce my resources accordingly.
I know that system gives low memory warnings & i can clean up my data there but even if sometimes it wont happen.
If i get to know that my app is reaching maximum memory & remaining size on heap so i could be better to reduce my resources.
Thanks in advance....
Use Instruments. Command-I in XCode to profile your app in Instruments.
Yes of course, I would recommend the instrument's tool "Leaks". It lets you know how much memory allocates your app, and if there are leaks it tells you what they are, when and were it was allocated (and obviously not released).
Here is a nice guide I used some time ago.
http://www.cimgf.com/2008/04/02/cocoa-tutorial-fixing-memory-leaks-with-instruments/
Related
I am developing an app that is crashing due to an excess of memory usage. I would like to know the amount of memory that is being used by each active thread so that I can decide which allocated or drawn in screen elements release or remove from view. Is there a way to obtain it?
I have tried using mach.h library but with mach_task_self() I can only access the memory used by the whole application.
Thanks in advance
I think what you want is logMemUsage().
You can check the Answer from this Question :
Watching memory usage in iOS
I think you can get something from this Documentation also :
Understanding and Analyzing iOS Application Crash Reports
If you want to check Memory Usage While Application is Running then use Instruments. :
Using Instruments you can check how much memory your app is using. In Xcode4, use 'Profile' build, choose Leaks, then click the Library button in the toolbar and add the Memory Monitor instrument.
If you really don't want to use Instruments then you can use Custom Class UIDeviceAdditions :
Get current Memory usage
Hope it's Enough.
You can't because threads share the heap. Threads are created with a 512KB stack space, with memory pages allocated as needed. Other than that, there is no memory per thread value stored anywhere.
I'm trying to get a feel for the amount of memory an iOS app can reliably allocate to help me drive some design decisions. The app is going to involve real time synchronised processed audio and animation.
Other than writing code that loads up the frameworks I'll need then trying to progressively allocate memory until I get warnings, is there any way to determine this kind of thing?
The simulator doesn't let you select a specific hardware model, so I assume I can't even simulate this stuff.
You cannot determine how much memory an app allocate as far as I know. Always try to keep the lowest memory possible for your app.
The memory allocated to your app depends on many factors like : number of background process happening, amount of memory available, memory used by other apps, the device you are running etc..
So, its not a good practice to keep a maximum line for memory consumed by your app and design accordingly.
Also try to hold only the necessary memory you need and handle memory issue in the memory callback methods like 'didreceivememorywarning'. Always consider that you have the least amount of memory allocated by the OS.
Is there a way to retrieve information about the memory of the ipad during running?
For example, i would like to print in the console the use of memory at t instant.
Thanks
You should instrument this instead of trying to print a number. That number is not really useful. What you care about is your application's dirty memory footprint for memory pressure on the device and how much code/mapped ro mem you're evicting to see if you're essentially thrashing and causing performance problems due to memory pressure.
The other info you can get, like device inboard memory and how many pages your app has allocated are not useful because you don't know how much of that memory is wired to other devices or the kernel and you don't know how many of your allocated pages are faults at that point.
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
I want to make sure I'm reading the allocations plug in correctly. I'm testing an iPad app thats receiving memory warnings 1,2 & 3.
I want to know the current used up memory from my app, which I think it has to be the "Live Bytes" column? which marks All Allocations to 2.42 MB which I think its low.
What do the other columns report? #Transitory, Overall Bytes ?
Also if my app uses only 3 MB of memory can it be killed if I get a memory level 3 warning without releasing?
Thank you.
Don't use the Object Allocations instrument for looking at your total memory usage. It does not display the true total memory size of your application, for reasons that I speculate about in my answer here.
Instead, pair Object Allocations with the Memory Monitor instrument, the latter of which will show the true total size of your application. I'm willing to bet that it's way larger than the 2.42 MB you're seeing in Object Allocations (for example, I had an application with 700k of memory usage according to ObjectAlloc, but its actual size was ~25 MB in memory). If you are receiving memory warnings on an iPad, your application is probably chewing up quite a bit of memory.
Object Allocations is handy for telling you what you have resident in memory, but it's not an accurate indicator of the size of those items. It's also a great tool for showing you steady increases in allocated objects by using the heap shot functionality (the "Mark Heap" button on the left-hand side of the instrument).
Your memory usage looks fine. Check to see which app is being sent the memory warnings, it is probably not your app assuming your app is not in the background. The only way you should be getting memory warnings is if the app is in the background and another app needs more memory.
When I was looking at logs I noticed other apps were getting them while my app was running, other apps such as Mail or navigation apps (Navigon) do run in the background and will cause memory pressure. You might get a memory warning but should not be terminated.
For a description of the memory columns see Explanation of Live Bytes & Overall Bytes.
As #Brad points out use the memory monitor tool as well.