From: Benjohn Barnes <benjohn@...>
Date: 2006-04-29T21:33:35+09:00
Subject: Re: Multiplexed I/O


On 29 Apr 2006, at 09:39, Vlad GALU wrote:

>    I'd like to use Ruby for a quite high performance networking tool.
> In practice, writing a multithreaded C/C++ program is not pheasible
> due to the large connection pool I plan to manage, which would impose
> a very scarce stack size. From what I can see, Ruby's default I/O
> semantics are synchronous. One can opt for using IO#select though.
> Let's just say synchronous is OK, API-wise. My question is: if I use
> one (Ruby) thread per client, would it block the whole Ruby
> interpreter while performing blocking I/O ? On my system (FreeBSD)
> ruby is linked against libpthread, for a good reason I guess. Could it
> be that it splits blocking routines to a separate (POSIX) thread ? If
> not, I'll probably end up replacing the select() implementation with
> kqueue() calls in the Ruby code.

I don't understand why you can't use c++ here, so I guess I'm missing  
something - my reason for not using c++ would be that I no longer  
enjoy programming with it :)

However...

I wrote a server recently that "talked" on numerous sockets to many  
clients. It would have seemed multi threaded to them, but was in fact  
single threaded. Here's a very simple version of it. It doesn't  
handle disconnections at all, but they are easy to add in. I was  
quite pleased that I could extend the socket objects to be able to  
polymorphically handle an event on them. I think it'll be pretty high  
performance, but I've no idea if that's true. It certainly doesn't  
need to poll, and it doesn't have to jump about in different thread  
contexts.

All the best,
	Benj


require 'socket'

$sockets = []

def process_sockets
	select($sockets)[0].each do |soc|
		soc.handle_event
	end
end

module Server
	def self.create_server(port)
		server = TCPServer.new(port)
		server.extend( self )
	end

	def handle_event
		$sockets << accept_connection
	end

	def accept_connection
		con = accept
		con.extend(Connection)
	end
end

module Connection
	def handle_event
		s = gets.chomp
		Kernel.puts "#{self} said #{s}"
		puts "You said #{s}"
	end
end

$sockets << Server.create_server(5001)
loop {process_sockets}