From: David Corbin <dcorbin@...>
Date: 2005-02-15T20:44:15+09:00
Subject: Re: Threading in Windows

On Tuesday 15 February 2005 04:05 am, Robert Klemme wrote:
> "William Morgan" <wmorgan-ruby-talk@masanjin.net> schrieb im Newsbeitrag
> news:20050214231001.GD26414@masanjin.net...
>
> > Excerpts from David Corbin's mail of 14 Feb 2005 (EST):
> > > > I'd be surprised if Ruby allowed more than one thread to do a
> > > > system() call at a time,
> > >
> > > Well, I could understand that (thought it would be bad).  But I'm sure
> > > that the three threads are running three process in parallel.
> >
> > Oh. Cool!
> >
> > > And what's more, none of the other threads will start until all the
> > > one of the first three finishes.  So, it's not just a limit of 3
> > > external processes (btw, looking at the source code, it looks like a
> > > limit of 255 external processes).
> >
> > Then I don't know. There are some Windows-specific and Thread-specific
> > blocking issues that I know of, but none of them have this behavior by
> > themselves.
>
> If processes are short lived it could simply be a timing issue.  

They are not.  I my spike, each thread was running for 5+ minutes.   I have 
sample code at the office that I'll try to post.

> The 
> overhead of creating a process is quite huge compared to that of creating
> a ruby or native thread.  And for example, if mem is low it'll take even
> longer to spawn a process.  Also, I noticed that Windows takes its time to
> shutdown a process - it even looks like all pages are swapped in from disk
> before the process is gone.  Dunno much about Windows internals though...
>
> Kind regards
>
>     robert