Is C# part of the problem?

[MadBlaster]

Hi. I read C# is popular and CLoD apparently uses it. I also read that it uses interpreter/JIT comp and managed heap/garbage collection. I read that the garbage collector kind of has a mind of it's own (non deterministic). Anyway, the garbage collection is suppose to put an end to the memory leaks? But, CLoD has the memory leaks??? So wtf is on that. I think maybe if you have to write the multi thread and the garbage collector is doing wtf, you gonna get some problems! Also, read JIT has some real-time overhead. So I wonder about that. So, did 1c just make a mistake with C# and this game and should have stuck with what they know like C or C++ or some other older imperative fully compiled language they have more experience in? Maybe C# just not a good choice?. Just my speculation as I read my compiler book. But it would be interesting to hear opinions from the progs on this board.

[Osprey]

There is a garbage collector in C# but it is best to dispose of objects with code yourself when they are finished with which is more efficient.

[Thee_oddball]

I remember reading this a while back...dont know if it applies though

Attempting to second-guess the garbage collector is generally a very bad idea. On Windows, the garbage collector is a generational one and can be relied upon to be pretty efficient. There are some noted exceptions to this general rule - the most common being the occurrence of a one-time event that you know for a fact will have caused a lot of old objects to die - once objects are promoted to Gen2 (the longest lived) they tend to hang around.

In the case you mention, you sound as though you are generating a number of short-lived objects - these will result in Gen0 collections. These happen relatively often anyway, and are the most efficient. You could avoid them by having a reusable pool of objects, if you prefer, but it is best to ascertain for certain if GC is a performance problem before taking such action - the CLR profiler is the tool for doing this.

It should be noted that the garbage collector is different on different .NET frameworks - on the compact framework (which runs on the Xbox 360 and on mobile platforms) it is a non-generational GC and as such you must be much more careful about what garbage your program generates.

[mazex]

From what I understand they use C# for the GUI and the scripting, just like IL2 used Java for the GUI... Most games use a more user friendly language for the scripting like Python (which is rather confusing in a way though ), the thing is that it comes without saying that the scripting part has to be JIT compiled

I'm pretty sure the game itself is coded in C++

Well - my oh my, at this point to not look silly I loaded Reflector to just verify that the core dll:s where C++ dll:s and not .NET and to my amazement the majority are really .NET assemblies, with a small bunch like the SpeedTree dll:s etc written in C++. Hmm, writing the core of a game like this in .NET feels very weird - I actually never thought of it as I was so sure that it was only the GUI and Scripting which felt OK...

A view in reflector of the core.dll that I thought was a C++ dll below... The "WLandscape" class in the image sure is a part of the render code that is in .NET as you can see... Or is it maybe just for the map editor? Nah, no need for "renderSunGlare" there?

coredll.jpg

EDIT: Interesting looking at the methods... Like cHQ_forestHeightHere(float x, float y)... Could be used to see if you should crash into a tree without actually checking the 3D tree object itself? And then there are a bunch of unmanaged types returned so there sure is interop going on (naturally)... Needs some more digging on what is done in C++ and what is done in .NET. I really don't understand why someone would come up with the idea to write a game like this in .NET. For an Indie game with no real preformance bottlenecks like Magica - sure. But this?

[WTE_Galway]

Also remember no garbage collector can stop resource leaks if the code is badly structured and leaves things open that are no longer needed. The garbage collector will just assume its left open for a reason and leave well enough alone.

[Thee_oddball]

Originally Posted by WTE_Galway

Also remember no garbage collector can stop resource leaks if the code is badly structured and leaves things open that are no longer needed. The garbage collector will just assume its left open for a reason and leave well enough alone.

so your saying that over a period of time alot of "stuff" is winding up in gen2?

[Thee_oddball]

Originally Posted by mazex

From what I understand they use C# for the GUI and the scripting, just like IL2 used Java for the GUI... Most games use a more user friendly language for the scripting like Python (which is rather confusing in a way though ), the thing is that it comes without saying that the scripting part has to be JIT compiled

I'm pretty sure the game itself is coded in C++

Well - my oh my, at this point to not look silly I loaded Reflector to just verify that the core dll:s where C++ dll:s and not .NET and to my amazement the majority are really .NET assemblies, with a small bunch like the SpeedTree dll:s etc written in C++. Hmm, writing the core of a game like this in .NET feels very weird - I actually never thought of it as I was so sure that it was only the GUI and Scripting which felt OK...

A view in reflector of the core.dll that I thought was a C++ dll below... The "WLandscape" class in the image sure is a part of the render code that is in .NET as you can see... Or is it maybe just for the map editor? Nah, no need for "renderSunGlare" there?

Attachment 8913

EDIT: Interesting looking at the methods... Like cHQ_forestHeightHere(float x, float y)... Could be used to see if you should crash into a tree without actually checking the 3D tree object itself? And then there are a bunch of unmanaged types returned so there sure is interop going on (naturally)... Needs some more digging on what is done in C++ and what is done in .NET. I really don't understand why someone would come up with the idea to write a game like this in .NET. For an Indie game with no real preformance bottlenecks like Magica - sure. But this?

get it to market faster?, use smaller team? or both. you think this maybe the reason for the micro stutters and leak?

[MadBlaster]

Originally Posted by Thee_oddball

get it to market faster?, use smaller team? or both. you think this maybe the reason for the micro stutters and leak?

This is my fear. I wish I could offer more insight, but I just started reading about programming since January and I never read a C# book. So very newbie. Interesting responses so far.

[mazex]

Originally Posted by Thee_oddball

get it to market faster?, use smaller team? or both. you think this maybe the reason for the micro stutters and leak?

Well, I started working as a C++ developer in the mid 90:ies and switched to C# in 2006 for those reasons so I agree, if it would have been a business application... C# is an easier language to work with in general and If you have a team that includes junior developers doing businesses applications there is no debate on what to choose, the benefits of the .NET framework for business apps is a real boost too, as you have base classes for most everyday needs like talking to web services, mail servers, mq servers etc..

For gaming though it's a different story... The benefits of all those base classes in the .NET framework are really minor as most of the code is maths anyway, and one can assume that game developers know how to allocate and deallocate memory as you can't just let the framework do your cleanup if you use millions of objects that is rare in a business app. You just can't have a GC collect when doing 100 fps. And you really need 100% performance and then C# is not the best language... Sure there are many claims lately that a well written C# program is just some percent slower than C++, the problem is that a sloppy C# program is not. You leave too much in the hands of the runtime, and when tuning performance you are not in full control. And then you have the problem that most of the external libraries that you use in a game are written in C++ (like directx and speedtree) so to use them you get what is called Interop, which is when you go from managed code to unmanaged code, where managed code is the C# code where the memory is managed by the. NET runtime as opposed to the unmanaged code written in C++. And interop costs peformance when you context switch between them. It works a lot better today than in the first versions of .NET and I remember a project where we tried to use a mixed C++ / C# in 2005 where we had to ditch it and go back to unmanaged code as the memory demand increased and we lost too much performance... And in the end it was not that much faster to use C# as it was a team of experienced C++ developers.

There are many games popping up these days written in C#, mainly by small indie teams using some generic 3D engine like Unity3D, but all the bleeding edge games are written in C++... And I don't see that changing as you loose control and performance to be able to have an easier programming language...

/mazex

[MadBlaster]

Good read Mazex. Maybe Luthier knows this now.