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Re: Slow pthread_create() under high load
- To: "Stephen C. Tweedie" <sct at redhat dot com>
- Subject: Re: Slow pthread_create() under high load
- From: Kaz Kylheku <kaz at ashi dot footprints dot net>
- Date: Mon, 27 Mar 2000 07:51:45 -0800 (PST)
- cc: sasha at mysql dot com, Alan Cox <alan at lxorguk dot ukuu dot org dot uk>, drepper at cygnus dot com, glibc-linux at ricardo dot ecn dot wfu dot edu, linux-kernel at vger dot rutgers dot edu, mysql at lists dot mysql dot com, monty at mysql dot com
- Reply-To: glibc-linux at ricardo dot ecn dot wfu dot edu
On Mon, 27 Mar 2000, Stephen C. Tweedie wrote:
> Date: Mon, 27 Mar 2000 12:24:16 +0100
> From: Stephen C. Tweedie <sct@redhat.com>
> To: sasha@mysql.com
> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>, drepper@cygnus.com,
Kaz Kylheku <kaz@ashi.footprints.net>, glibc-linux@ricardo.ecn.wfu.edu,
linux-kernel@vger.rutgers.edu, mysql@lists.mysql.com, monty@mysql.com,
Stephen Tweedie <sct@redhat.com>
> Subject: Re: Slow pthread_create() under high load
>
> This is part of a kernel defence mechanism, and yes, it is important to
> do something like this. If you don't, then a user can create a fork-
> bomb task which continually forks off children, and if the children and
> parent all keep the same credits, then it becomes essentially
> impossible for any other process ever to get scheduled. It is a _nasty_
> denial-of-service attack, and that's why the kernel has to share the
> scheduling credits out when you fork.
So what you are saying is that we effectively have that behavior which is
called ``process scope scheduling'' for threads. Would this be accurate, or is
it something more ``organic'' in between process scope and system scope?