Subject: Re: Scheduler hints
To: M. Warner Losh <imp@bsdimp.com>
From: Roland Dowdeswell <elric@imrryr.org>
List: tech-kern
Date: 12/09/2002 04:44:48
On 1039422164 seconds since the Beginning of the UNIX epoch
"M. Warner Losh" wrote:
>

>There are a number of flaws in the arguments put forth against the
>patch:
>
>	1) A system on the edge will be tottered over: This is true
....
>	2) Rampant forkers.  This will hurt them.  These beasts should
....

I think that it would be unfair to characterise my arguments as
either of these.  If you examine the patch, you will find that the
.5s pause is invoked if a process reaches its user process limit.
A single program forking off 160 children/grandchildren/etc is by
no means a system on the edge of being tottered over.  It could
be, e.g. a web server responding to an uncharacteristically large
number of requests if, e.g. the web server has been /.ed.  With
the change, as I pointed out, certain programs, such as thttpd,
are very likely to completely fail where before they would just
happily churn along giving a few failures here and there.

>	3) But with the one slot, a sysadmin could regain the system.

I don't think that there is any general consensus here that upping
the number of root-only slots is a bad idea.

--
    Roland Dowdeswell                      http://www.Imrryr.ORG/~elric/