From: Ben Schumacher <ben@...>
Date: 2002-10-04T04:17:41+09:00
Subject: Re: Please help, question regarding threads

Bulat Ziganshin wrote:
> Hello Yohanes,
> 
> Thursday, October 03, 2002, 12:09:01 PM, you wrote:
> 
>>>I am working on a server-oriented application which is threaded, each
>>>connection to the server creates a new thread
>>
> 
> YS> So, in the end, if you see that your number of threads are growing in
> YS> step with the number of connection, perhaps it is time for you to
> YS> re-evaluate the design.
> 
> if he writes server, not client, it is better to use one thread per
> connection. also, ruby threads are very light and IMHO you can't save
> time by simulating thread switching in your own code

Would you care to explain why? I can give you a great example of at 
least one protocol where setting a thread per connection is a terrible 
idea, XMPP (Jabber). Since the protocol expects the user to setup a 
long-running socket per user, even though the traffic across this socket 
is relatively low, a thread per connection would kill your scalability.

If the usage of these sockets is short-lived, and there is a limited 
number of connections established, I can understand a thread per 
connection, as it make design significantly easier. However, this 
imposes scalability restrictions on your software at design time, and 
should you decide later you need more scalability in your software, 
you'll have to throw more money, either in the form of bigger hardware, 
or time refactoring.

Admittedly, I don't know all the specifics around the design of ruby's 
thread implementation, but I would venture a guess that a thread per 
socket in any software where you need a highly scalable network server 
is a bad idea. Keep in mind, however, that the thread implementation in 
ruby (the C interpreter) is likely to be radically different from an 
implementation in JRuby (the Java interpreter).

bs.