From nobody@FreeBSD.org  Thu Jun 14 05:47:31 2001
Return-Path: <nobody@FreeBSD.org>
Received: from freefall.freebsd.org (freefall.freebsd.org [216.136.204.21])
	by hub.freebsd.org (Postfix) with ESMTP id 84C2637B408
	for <freebsd-gnats-submit@FreeBSD.org>; Thu, 14 Jun 2001 05:47:31 -0700 (PDT)
	(envelope-from nobody@FreeBSD.org)
Received: (from nobody@localhost)
	by freefall.freebsd.org (8.11.3/8.11.3) id f5EClVW14680;
	Thu, 14 Jun 2001 05:47:31 -0700 (PDT)
	(envelope-from nobody)
Message-Id: <200106141247.f5EClVW14680@freefall.freebsd.org>
Date: Thu, 14 Jun 2001 05:47:31 -0700 (PDT)
From: Thierry Herbelot <thierry@herbelot.com>
To: freebsd-gnats-submit@FreeBSD.org
Subject: the Hz kernel config option is not documented
X-Send-Pr-Version: www-1.0

>Number:         28143
>Category:       docs
>Synopsis:       the Hz kernel config option is not documented
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    asmodai
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          doc-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Jun 14 05:50:01 PDT 2001
>Closed-Date:    Thu Nov 15 12:52:06 PST 2001
>Last-Modified:  Thu Nov 15 13:00:43 PST 2001
>Originator:     Thierry Herbelot
>Release:        FreeBSD 4.3-Release
>Organization:
>Environment:
FreeBSD pc-bsd60.XXX 4.3-RELEASE FreeBSD 4.3-RELEASE #11:
Tue Apr 24 19:14:23 CEST 2001     
herbelot@pc-bsd60.XXXX:/usr/obj/usr/src/sys/station  i386
>Description:
The Hz kernel config option is referenced in the ipfw(8) man page 
(typically 10ms, but it is a good practice to run kernels with 
``options HZ=1000'' to reduce the granularity to 1ms or less) but is
nowhere to be seen in the usual kernel config help file (aka LINT) or 
in a man page (and neither in the handbook).

I am using HZ=5000 in some (around 100) PCs here, with no ill effects. 
As this feature is a great win for xxBSD (for example for real-time 
systems), it should be documented.
>How-To-Repeat:

>Fix:
Add a doc line in the LINT config file:
-----------------------------
options HZ=1000 # set the system clock to 1000 Hz 
                # (values above above 5000Hz should not be used)
-----------------------------
>Release-Note:
>Audit-Trail:
Responsible-Changed-From-To: freebsd-doc->asmodai 
Responsible-Changed-By: ru 
Responsible-Changed-When: Thu Jun 14 05:53:08 PDT 2001 
Responsible-Changed-Why:  
Jeroen's commit to sys_i386_conf/NOTES,v 1.760 could be MFC'ed. 

http://www.FreeBSD.org/cgi/query-pr.cgi?pr=28143 
State-Changed-From-To: open->closed 
State-Changed-By: asmodai 
State-Changed-When: Thu Nov 15 12:52:06 PST 2001 
State-Changed-Why:  
MFC'd to 4.4-STABLE as of today. 

Thanks! 

http://www.FreeBSD.org/cgi/query-pr.cgi?pr=28143 
>Unformatted:
