Subject: Re: NetBSD is not Linux
To: Stephane St Hilaire <email@example.com>
From: Matthias Buelow <firstname.lastname@example.org>
Date: 06/11/2001 23:06:13
Stephane St Hilaire writes:
>I'm not sure what is your point... Is 4090 processes an insufficient number
>? Does a program made up of one executable/two threads require more
>ressources and run slower than a program that forks itself up and uses twice
>the amount of memory ? Are you saying that threads are not useful in an OS
>and should never be a part of NetBSD ?
The problem wojtek was probably hinting at is, since lignux maps
each user library thread onto one kernel process entry, running
applications which use many threads (like, several thousand) is
prohibitive, from a resource consumption pov, and often simply not
possible, when the number of threads is larger than the max number
of proctable entries.
Normally, thread libraries multiplex many user threads onto a few
system threads so that problem is not so serious there. This seems
not to be the case with the linuxthreads libraries, however.
 You might say applications with several thousand threads do
not exist? Think of server applications that don't use the
poll(2)/select(2) mechanism for i/o multiplexing and instead use
a single thread per client connection. Such a thing should be
fairly common in the Windoze "server" world, for example. Also,
with the broader acceptance of Java[tm], there would be an increased
base of thread-hungry server applications.