Building a server to manage high concurrent connections is non-trival task. For those developers that use ActionScript 3 to build games on the client side it means having a totally different skillset. Being able to use ActionScript 3 on the server to build MMO’s or port client code to the server allows developers to leverage their skills on the server. By walking through a live game example with more then 15,000 concurrent connections running on a medium Amazon EC2 server the presentation will: 1. Introduce Linux server configuration for high concurrent connected usage. 2. Introduce Socket class based on libev library for high concurrent connection. 3. Introduce leveraging Tamarin project for ActionScript 3 on the server.

1. 构建 ActionScript 游戏服务器，
支持超过 15000 并发连接
Building an ActionScript Game Server with over
15,000 Concurrent Connections
Renaun Erickson
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2. Basic MMO Game Architecture
• Clients
• Servers
• Databases
• Networking
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3. MMO Network Considerations
• Protocols (TCP, UDP, HTTP)
• Firewalls
• Latency
• Packet Size
• Data Schema
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4. Have to be able to create large
number of connections that can
send packets at a reasonable rate
and bandwidth
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5. Socket Implementations
• Check each file descriptor each frame
– Select, poll
• Slow for large number of connections
• OS Optimized
– Epoll, kqueue, /dev/poll, pollset, I/O Completion
Ports
• OS specific fast implementations
• Event based libraries
– Libevent and libev
• Fast for large number of connections
• Portable code, hides OS specific implementations
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6. Server Configuration
• Tell OS to allow large number of file
descriptors
• Tell OS how much ram for each file
descriptor
• Tell OS buffer sizes for network protocols
• Tell OS what ports range to use, only 65k
ports per IP
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7. Flash on the Client and Server
• Many MMOs in China use Flash as the
Client
• Server naturally has MMO game logic
• Put game logic on server for security
• Many benefits of using the same
language on client and server
Is ActionScript on the server possible?
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8. ActionScript on the Server
• Flash Player Dissected
– Core – VM, Primitives, ActionScript syntax
– APIs – C/C++ classes implementing rich Flash
Player API and features
• Tamarin
– Open sourced core parts of the Flash Player
– No rich API or features, you have to write
them yourself
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9. Tamarin Projects
• Thane (part of Whirled SDK by ThreeRings)
– http://wiki.whirled.com/Whirled_SDK
• Redtamarin (by zwetan and others)
– http://code.google.com/p/redtamarin/
• PushButton Engines Network component by
Ben Garney
– https://github.com/PushButtonLabs/PBNetwork
ing
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10. Case Study: SpellTraction
Design By: Garth Braithwaite http://www.garthdb.com/ @garthdb
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11. Live Demo and Source Code
• http://renaun.com/serveras/test
• http://renaun.com/serveras/spelltraction/
• https://github.com/renaun/ActionScriptGa
meServerExamples
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12. Server Setup
• Game Server
– Amazon EC2 Medium Server
– 64 bit Ubuntu OS
– Running two game instances
• Main
• Load Test
• Load Test Server
– Amazon EC2 Medium Server
– Custom test scripts
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13. Server Code
• Redtamarin
– Created ServerSocket.as – libev socket
implementation
– Compile ActionScript files into ActionScript
Byte Code (abc files)
– Command line redtamarin shell runs the abc
files
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14. Server ActionScript Code
function loopHandler():void
{
if (!ss.listening)
ss.listen("10.111.33.190", 12122);
else
serverBrain.beat(); // Game Tick
}
var serverDispatcher:SocketServerNerveDispatcher
= new SocketServerNerveDispatcher();
var serverBrain:ServerBrain = new ServerBrain();
var serverNerve:ServerNerveSystem
= new ServerNerveSystem(serverBrain, serverDispatcher);
serverBrain.addNerve(serverNerve);
var ss:ServerSocket
= serverDispatcher.createServerSocket(serverNerve);
ss.loop.add(loopHandler);
ss.start(250);
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15. Libev Socket Implementation
bool ServerSocketObject::_listen(Stringp host, const int port)
{
struct socket_io w_accept;
StUTF8String hostUTF8(host);
const char* hostAddr = hostUTF8.c_str();
if( (w_accept.fd = socket(PF_INET, SOCK_STREAM, 0)) < 0 ) return false;
int flags = fcntl(w_accept.fd, F_GETFL, 0);
fcntl(w_accept.fd, F_SETFL, (flags > 0 ? flags : 0) | O_NONBLOCK);
sockaddr_in addr;
memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = inet_addr(hostAddr);
addr.sin_port = htons(port);
int status = bind(w_accept.fd, reinterpret_cast<struct sockaddr *>(&addr), sizeof(addr));
if (status != 0) return false;
_socket = w_accept.fd;
if (listen(w_accept.fd, 2) < 0) return false;
w_accept.socketObject = this;
// Initialize and start a watcher to accepts client requests
ev_io_init(&w_accept.io, accept_cb, w_accept.fd, EV_READ);
ev_io_start(loop_ev, &w_accept.io);
ev_loop(loop_ev, 0);
return true;
}
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16. Linux Kernel Configurations
/etc/sysctl.conf
net.core.rmem_max = 33554432
net.core.wmem_max = 33554432
net.core.rmem_default = 1048576
net.core.wmem_default = 1048576
net.core.optmem_max = 33554432
net.ipv4.tcp_rmem = 4096 4096 33554432
net.ipv4.tcp_wmem = 4096 4096 33554432
net.ipv4.tcp_mem = 786432 1048576 26777216
net.ipv4.tcp_max_tw_buckets = 360000
net.core.netdev_max_backlog = 30000
net.ipv4.ip_local_port_range = 2048 65535
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_no_metrics_save = 1
net.core.somaxconn = 131072
fs.file-max = 131072
/usr/include/linux/limits.h
NR_OPEN = 65536
/etc/security/limits.conf
* soft nofile 65535
* hard nofile 65535
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17. Client Code
Client
Shared Code
Server
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18. Q/A
renaun@adobe.com
http://github.com/renaun
@renaun
http://renaun.com/blog
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