From: khaines@...
Date: 2007-01-29T03:54:25+09:00
Subject: Re: Benefits of Multi-Threading?

On Mon, 29 Jan 2007, Justin Collins wrote:

> There are two main reasons for using multi-threaded applications, even on a 
> single processor:
>
> The first is performance. It's faster to switch between threads than it is 
> between processes, and it's (typically) even faster to switch between 
> user-level threads like Ruby has. Also, any asynchrony in your program (like

That's a bit of a red herring, though.  With Ruby's green threads, every 
active (i.e. not sleeping) thread that is added to a single process 
reduces the overall throughput of all of the threads, collectively, by a 
noticable amount.  While two separate processes on a single processor may 
have less throughput than two threads in a single ruby process, those two 
threads will have less throughput than a single thread.  So, a single 
thread solution will typically be more performant than multi-thread 
solution under Ruby's current threading model.


Kirk Haines