I have developed a winforms application using C# in VS2008. When I run this application I observed in task manager that it shows 80 MB of memory is consumed.
How can I reduce this? Even very small applications also take 8 MB of memory...
What can I do to reduce the memory footprint?
Thank you very much in advance.
The task manager memory number is not always as sharp as it would be, however this small trick can cheat that number... Not meant for production
public static void RefreshMemory() {
try {
Process curProc = Process.GetCurrentProcess();
curProc.MaxWorkingSet = curProc.MaxWorkingSet;
} catch {
// Handle the exception
}
}
It would be helpful also to trace the memory objects usage with a tool like JetBrains dotTrace or another similar.
Your question clearly smells of premature optimization.
You should tackle memory usage only in the following situations :
You're developing for a device which hasn't a lot of memory available (with the portable .net framework for example)
You're reaching the limit of .net in term of memory size (ie around 1.3gbp)
Your customers are complaining.
Don't get me wrong, this doesn't mean you must waste memory or that you shouldn't take memory in consideration while coding. I just mean that in your case, memory usage is probably not a big deal.
Well, the .NET framework has a fairly significant overhead -- the simplest possible "hello world" console app has a 4 mb working set, as you have observed. There are a number of things you can do to reduce the memory footprint (reduce embedded resources, be sure to build in Release configuration, etc.)
But at the end of the day, .NET is designed for developer efficiency over memory/resource efficiency, so if you have an app that has to run in a very small efficient memory space you should consider writing it in C++ or some other language where you manage your own resources.
In addition to all the previous good comments, please remember that the numbers you are seeing in Task Manager are virtual memory, not physical memory. The actual amount of physical RAM used by the program is not obvious from looking at Task Manager. Also, Task Manager is showing you a series of snapshots - if you really had a problem, you'd want to look at it over time, with Perfmon or something, in addition to the excellent suggestion on profiling with JetBrains' dotTrace.
But don't do any optimization until your code works, and has high test coverage, and until you know what actually needs to be optimized. Otherwise, you run the risk of optimizing problems that don't exist, and worse, of optimizing the wrong problem, while ignoring the real problem or possibly making it worse.
Related
I understand there are many questions related to this, so I'll be very specific.
I create Console application with two instructions. Create a List with some large capacity and fill it with sample data, and then clear that List or make it equal to null.
What I want to know is if there is a way for me to know/measure/profile while debugging or not, if the actual memory used by the application after the list was cleared and null-ed is about the same as before the list was created and populated. I know for sure that the application has disposed of the information and the GC has finished collecting, but can I know for sure how much memory my application would consume after this?
I understand that during the process of filling the list, a lot of memory is allocated and after it's been cleared that memory may become available to other process if it needs it, but is it possible to measure the real memory consumed by the application at the end?
Thanks
Edit: OK, here is my real scenario and objective. I work on a WPF application that works with large amounts of data read through USB device. At some point, the application allocates about 700+ MB of memory to store all the List data, which it parses, analyzes and then writes to the filesystem. When I write the data to the filesystem, I clear all the Lists and dispose all collections that previously held the large data, so I can do another data processing. I want to know that I won't run into performance issues or eventually use up all memory. I'm fine with my program using a lot of memory, but I'm not fine with it using it all after few USB processings.
How can I go around controlling this? Are memory or process profilers used in case like this? Simply using Task Manager, I see my application taking up 800 MB of memory, but after I clear the collections, the memory stays the same. I understand this won't go down unless windows needs it, so I was wondering if I can know for sure that the memory is cleared and free to be used (by my application or windows)
It is very hard to measure "real memory" usage on Windows if you mean physical memory. Most likley you want something else like:
Amount of memory allocated for the process (see Zooba's answer)
Amount of Managed memory allocated - CLR Profiler, or any other profiler listed in this one - Best .NET memory and performance profiler?
What Task Manager reports for your application
Note that it is not necessary that after garbage collection is finished amount of memory allocated for your process (1) changes - GC may keep allocated memory for future managed allocations (this behavior is not specific to CLR for memory allcation - most memory allocators keep free blocks for later usage unless forced to release it by some means). The http://blogs.msdn.com/b/maoni/ blog is excelent source for details on GC/memory.
Process Explorer will give you all the information you need. Specifically, you will probably be most interested in the "private bytes history" graph for your process.
Alternatively, it is possible to use Window's Performance Monitor to track your specific application. This should give identical information to Process Explorer, though it will let you write the actual numbers out to a separate file.
(A picture because I can...)
I personaly use SciTech Memory Profiler
It has a real time option that you can use to see your memory usage. It has help me find a number of problems with leaking memory.
Try ANTS Profiler. Its not free but you can try the trial version.
http://www.red-gate.com/products/dotnet-development/ants-performance-profiler/
I wrote a hello world program (windows application without any UI) in C#. The release-build excutable doesn't do anything but to Thread.Sleep(50000) //50 seconds.
I opened sysinternals (a profiler like task manager). This excutable ate 7MB memory (private bytes)!!
Can anybody explain what is happening and how to make the memory usage smaller.
P.S. I also tried to use NGEN to pre-compile the .exe but still got the same memory usage.
Thanks a lot
C# (and other JIT compiled/interpreted languages) usually end up doing a lot of things for you automatically in the background. While what you've written is simple, there's a lot of stuff going on in the background to support the JIT nature of the application.
That 7MB of memory is relatively small given 2GB of RAM is fairly commonplace these days. And it probably won't go up more unless you do something unusual or allocate lots of arrays and data structures.
If it's a Hello World based on the C# WindowsApplication project type, and there's an int main in Program.cs doing an application.run on a Windows Form, then not only is there a lot of JIT overhead, but there's a lot of Windows Forms overhead too.
End of the day, I'm sure everything is dandy.
.Net apps have a lot of basic overhead, but your memory increase should be relatively small after that point.
Example. My one app consumes 10MB of memory on load, but it only consumes 40MB of memory after loading 60k rows from a Database, each row containing multiple strings and many values.
A small fixed upfront value isn't that bad, on modern computers. Scalability is the primary issue now-a-days. .Net scales fairly well for being managed.
How I can get the actual memory used in my C# application?
Task Manager shows different metrics.
Process Explorer shows increased usage of private bytes.
Performance counter (perfmon.msc) showed different metrics
when I used .NET memory profiler, it showed most of the memory is garbage collected and only few Live bytes.
I do not know which to believe.
Memory usage is somewhat more complicated than displaying a single number or two. I suggest you take a look at Mark Russinovich's excellent post on the different kinds of counters in Windows.
.NET only complicates matters further. A .NET process is just another Windows process, so obviously it will have all the regular metrics, but in addition to that the CLR acts as a memory manager for the managed application. So depending on the point of view these numbers will vary.
The CLR effectively allocates and frees virtual memory in big chunks on behalf of the .NET application and then hands out bits of memory to the application as needed. So while your application may use very little memory at a given point in time this memory may or may not have been released to the OS.
On top of that the CLR itself uses memory to load IL, compile IL to native code, store all the type information and so forth. All of this adds to the memory footprint of the process.
If you want to know how much memory your managed application uses for data, the Bytes in all heaps counter is useful. Private bytes may be used as a somewhat rough estimate for the application's memory usage on the process level.
You may also want to check out these related questions:
Reducing memory usage of .NET applications?
How to detect where a Memory Leak is?
If you are using VS 2010 you can use Visual Studio 2010 Profiler.
This tool can create very informative reports for you.
If you want to know approximately how many bytes are allocated on the GC heap (ignoring memory used by the runtime, the JIT compiler, etc.), you can call GC.GetTotalMemory. We've used this when tracking down memory leaks.
Download VADump (If you do not have it yet)
Usage: VADUMP.EXE -sop [PID]
Well, what is "actual memory used in my C# application" ?
Thanks to Virtual memory and (several) Memory management layers in Windows and the CLR, this is a rather complicated question.
From the sources you mention the CLR profiler will give you the most detailed breakdown, I would call that the most accurate.
But there is no 'single number' answer, the question whether Application A use more or less memory than B can be impossible to answer.
So what do you actually want to know? Do you have a concrete performance problem to solve?
I was hoping someone could explain why my application when loaded uses varying amounts of RAM. I'm speaking about a compiled version that uses the exe directly. It's a pretty basic applications and there are no conditional branches in the startup of the application. Yet every time I start it up the RAM amount varies from 6MB-16MB.
I know it's on the small end of usage anyways but I'm curious of why this happens.
Edit: to give a bit more clarification on what the app actually does.
It is a WinForm project.
It connects to a database using sqlclient to retrieve a list of servers.
Based on that list a series of buttons are created to start and stop a service on those servers.
Using the System.Timers class to audit the status of the services on those servers every 20 seconds.
The applications at this point sits there and waits for user input via one of the button clicks to start/stop the service.
The trick here is that the amount of RAM reported by the task schedule is not the amount of RAM used by your application. Rather, it is the amount of RAM reserved for use by your application.
Remember that with managed frameworks like .Net, you don't request or release memory directly. Rather, a garbage collector manages the memory for you. The amount of memory reserved for your application at a given time can vary and depends on a lot of different factors, including memory pressure created at the time by other programs.
Think of it this way: if you need 10 MBs of RAM for your app, is it faster to request and return it to the operating system 1 MB at a time over 10 requests/releases or reserve the block at once with one request/release? Now extend that to a scenario where you don't know exactly how much RAM you'll need, only that it's somewhere in the neighborhood of 10 MB. Additionally, your computer has 1 GB sitting there unused. Of course the best thing to do is take a good-sized chunk of that available RAM. Even 20 or 30 MB wouldn't be unreasonable relative to the ram that's sitting there unused, because unused RAM is wasted performance.
If your system later starts to feel some memory pressure then .Net can easily return some RAM to the system. This is one of the ways managed languages can sometimes give better performance than languages like C++ with traditional memory management: a garbage collector that can more easily take the entire system health into account when allocating memory.
What are you using to determine how much memory is being "used". Even with regular applications Windows will aggressively allocate unused memory in advance, with .NET applications it's even more complicated as to how much memory is actually being used, and how much Windows is just tacking on so that it will be available instantly when needed. If another application actually asks for memory this reserved memory will be repurposed.
One way to check is to minimize the application (at least on XP). If you are looking at the memory use in something like task manager you'll notice it drops off right away, eliminating the seemly "random" amount allocated.
It may be related to the jitter, after the first load the jitter already created a compiled version and it doesn't need to run. Other than that you would have to give us some more details about the app and which kind of memory you are referring to.
I have a long running console app running through millions of iterations. I want to benchmark if memory usage increases linerally as the number of iterations increases.
What would be the best way to go about this?
I think I really only need to be concerned with Peak memory usage during a run right? I basically need to work out what is the max number of iterations I can run on this hardware given the memory on the Server.
I am going to setup a batch lot of runs and Log the results over different interation sizes and then graph the results to identify a memory usage trend which can then be extrapolated for any given hardware.
Looking for advice on the best way to implement this, what .net methods, classes to use or should I use external tools. This article http://www.itwriting.com/dotnetmem.php suggests I should profile my own app via code to factor out shared memory used by the .net runtime across other apps on the box.
Thanks
There are several ways to do this:
Perfmon UI
You can use the Performance Montior control panel applet (in Administrative Tools) that comes with Windows to monitor your application. Have a look at the .Net CLR Memory category and the counters inside it. You can also limit the monitoring to just your process. This is probably the easiest as it requires no code changes.
Perfmon API
You can programmatically use performance counters from .Net. For this, you'll need to use the PerformanceCounter class. This is just an API to the same underlying information that the above UI presents.
Memory Profiler
You can use a memory profiler to profile you application whilst it is running. The two I have used with success are the ANTS Memory Profiler from RedGate and the .Net Memory Profiler from SciTech. Again, this requires no code changes, but may cost you money (although there are free trial versions). There is also the CLR Profiler (a howto can be found here).
Roll Your Own
You can get hold of some limited memory information from the Process class. Get hold of the current process using Process.GetCurrentProcess(), and then look at the properties of it, specifically the ones relating to memory (MinWorkingSet, MaxWorkingSet, PagedMemorySize64, PeakPagedMemorySize64, PeakVirtualMemorySize64, PeakWorkingSet64, PrivateMemorySize64, VirtualMemorySize64, WorkingSet64). This is probably the worst solution as you have to do everything yourself, including data collection and reporting.
If all you are wanting to do is to verify your application doesn't linearly increase its memory usage as your the number of iterations increases, I would recommend monitoring using the Performance Monitor UI in Windows. It will show you what you need with minimal effort on your part.
Windows perfmon is great for this kind of stuff. You have counters for all the managed heaps and for private bytes, if you need to cross correlate with iteration counts you can publish your own perfmon counters from .Net.
when you want to profile the mem usage of your apps, here is a piece of code you can use.
First you have to declare an instance of the PerformanceCounter class
Assembly a = Assembly.GetExecutingAssembly();
_PerfCounter = new PerformanceCounter(".NET CLR Memory",
"# Bytes in all Heaps",
a.GetName().Name,
true);
and each time you want to log the memory consumption you can call
_PerfCounter.NextValue()
Hope it was helpful
Maybe this tool can do everything you want.
Better late than never, but in response to M3ntat's comment, you'll need to add ".vshost" onto the assembly name parameter if you're running from within Visual Studio, e.g.
a.GetName().Name + ".vshost"