[MUD-Dev] Re: Java I/O and threads.

Elis Pomales pomales at caip.rutgers.edu
Mon Jan 25 16:39:46 New Zealand Daylight Time 1999

Using pine! cheer!

On Mon, 25 Jan 1999, Jo Dillon wrote:

> Elis Pomales (pomales at caip.rutgers.edu) spake thusly:
> > The current dilemma, is whether I should use threads on a per player (per
> > socket) basis, or implement a polling loop and queue player commands,
> > handling one command per player per loop cycle. The problem with having a
> > thread per player is the context switching overhead. The problem with the
> > polling loop is that I have to check each player to see if they have
> > input. (There is no select() in Java.) Furthermore, processing one command
> > per player may make the system very unresponsive??? Making it seem turn
> > based? 
>   I believe there's no non-blocking I/O either, so as you've foreseen
> it wouldn't be a good plan. It could leave the mud locked up indefinitely,
> in fact ;) With Java your best bet is one thread per socket, I should think.

Yes non-blocking calls can be done by setting So_Linger (I'm at work so
don't ask for specifics :)
So the question still stands :).  

> > What solutions have you guys (and gals?) employed in your servers? 
> > I guess one way to use the polling loop would be to keep each command as
> > small as possible...
> > 
> > PS. I would still use more threads, one for NPC's and one for the game
> > world.
> > 
> > PSS. Is having 100+ threads really that bad? (I would think so)
>   Not necessarily - it depends on your hardware and OS. Java's designed
> to use lots of threads so it's not too much of a worry.

Yes maybe, but if the threads are native threads then we are really
running into context switches...

> -- 
> 	Jo

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