• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
Mayouuu

Begining UDP Gaming Server: Best practises?

6 posts in this topic

Hi,

I am new to gaming server development, i am currently starting a new server, my first one and a huge one :D
I have allways programmed in C/C++, i come from embedded systems programming in pure C in the las year :D, now i have been told that developing that gaming server/framework will be much easier in C#, so I am in the way :)

The gaming server goal is to be able to manage 50k clients using some normal hardware, core i7 4-8 cores, 12Gb of RAM ....etc... some good machine but not a NASA one :D

I have made one layer that will accept and Log in gamers into the server using TCP, TCP will be used for login and some kind of ping with every user. This part seems to be working at the moment.

I have a thread that is getting datagrams from udpInputSocket of the server, it will only take that datagrams from every user and delegate them to other stage that will process them in many stages/threads.

Now what I am trying to do is just taking every datagram from every user (currently simulating 1k users) and then re-stream this packet to every user, the problem is that it is taking too long.... it is so so slow compared to the UDPReceiveThread.....

The thing here is that the receive thread enqueues every message received and the "broadcaster" thread is taking every queued message and sending it to each of the 1k users, this seems a huge task as it is running so slowly, i just loop over every messange and the over ever client calling socket.SendTo(.........).

The main question here is, am I doing it as it should be done? is it a matter of more "broadcaster threads" needed? or am I missing something like socket multicasting or broadcasting. I think I can´t broadcast or multicast becouse we are not aiming at LAN gaming rather than online internet gaming and i don´t know if in that scenario we can use that broadcast/multicast techniques.

Any help or suggestions in my new challange??

Thank you very much to every body! :D


PD: This would be the "broadcaster thread":


[CODE]
private void UDPBroadCastThread()
{
List<String> broadcastQueue = new List<string>();
ASCIIEncoding encoder = new ASCIIEncoding();
byte[] buffer;
_udpSendSocket.SendTimeout = 1; //Miliseconds timeout
while (true)
{
if (broadcastQueue.Count > 0)
{
for (int i = 0; i < broadcastQueue.Count; i++) // Loop through List of messages to broadcast
{
// Wait until it is safe to enter.
_clientsListMutex.WaitOne();
for (int client = 0; client < _myClientsList.Count; client++) // Loop through every user
{
buffer = encoder.GetBytes(broadcastQueue[i]);
int bytesSent = 0;
bytesSent = _udpSendSocket.SendTo(buffer, broadcastQueue[i].Count(), 0, (EndPoint)_myClientsList[client]._clientUDPEndPoint);
if (bytesSent != broadcastQueue[i].Count())
{
Console.WriteLine("Error sending data: {0}", broadcastQueue[i]);
}
}
// Release the Mutex.
_clientsListMutex.ReleaseMutex();
}
broadcastQueue.Clear();
}
else
{
Thread.Sleep(10);
// Wait until it is safe to enter.
this._broadCastMutex.WaitOne();
broadcastQueue = (List<String>)this._newBroadcastQueue;
this._newBroadcastQueue = new List<String>();
// Release the Mutex.
_broadCastMutex.ReleaseMutex();
}

}
}
[/CODE] Edited by Mayouuu
0

Share this post


Link to post
Share on other sites
Have you profiled the loop? Does it actually saturate one CPU core?

I would expect that the network buffer would fill up, and the UDP send function might block, stalling execution. If that happens, you know that you're trying to send more data than your network link can handle. The only way around that problem is to send less! (design for less bandwidth)

Another option is that the byte encoding takes too long, or returns too big an array. Because the bytes are the same each time you send them, you can encode once, outside the loop, and re-use the array each time you call send.

But this is just guessing -- knowing for sure what the problem is requires profiling and perhaps some network analysis. I know for a fact that a single thread with a good network card and good network link and sufficient buffering can easily do 250,000 UDP packets per second, and likely much more.
0

Share this post


Link to post
Share on other sites
Thank you very much for your reply, it is an N*N problem, it is not scalable so i think we have to modify the server structure, it will not re-stream to every client, it will create a message and send it to every user, this way the numer of sendTo calls(and bandwidth) will sacale more linearly and not exponentially, i think this will make the server much more responsive for 50k users :D, i am working on that idea now...
0

Share this post


Link to post
Share on other sites
The scaling you had was quadratic, not exponential. But that is still bad enough.

A common way to handle that is to use octree to partition a 3D world into dynamic sub sections. This will add a linear cost, but it will no longer be quadratic. I think it will be something like O(n*log(n)).
0

Share this post


Link to post
Share on other sites
Are you sure you should go for UDP instead of TCP? Yes, UPD is more efficient, in theory. But that means you have to implement all the control structures yourself. This can be quite difficult to get right, and efficient at the same time. While the TCP implementation is very optimized and optimal. And easier to use.
0

Share this post


Link to post
Share on other sites
Without profiling there is no point, you are just guessing. At the very minimum though you should move the encoding out of the client loop. Also shouldn't you have a mutex around the broadcast queue?
0

Share this post


Link to post
Share on other sites
I think there is another simple option for your problem. You could use ThreadPool class to send the data.
[CODE]ThreadPool.QueueUserWorkItem( s=> (_udpSendSocket.SendTo(buffer, broadcastQueue[i].Count(), 0, (EndPoint)_myClientsList[client]._clientUDPEndPoint));[/CODE]
EDIT: And set the number of worker threads at about 20(mabye even 30). Edited by dburner
0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0