From owner-freebsd-stable Tue Jan 23 12:12:54 2001 Delivered-To: freebsd-stable@freebsd.org Received: from netau1.alcanet.com.au (ntp.alcanet.com.au [203.62.196.27]) by hub.freebsd.org (Postfix) with ESMTP id C3BCA37B402 for ; Tue, 23 Jan 2001 12:12:34 -0800 (PST) Received: from mfg1.cim.alcatel.com.au (mfg1.cim.alcatel.com.au [139.188.23.1]) by netau1.alcanet.com.au (8.9.3 (PHNE_22672)/8.9.3) with ESMTP id HAA17284 for ; Wed, 24 Jan 2001 07:12:29 +1100 (EDT) Received: from gsmx07.alcatel.com.au by cim.alcatel.com.au (PMDF V5.2-32 #37640) with ESMTP id <01JZ9ZCL573K8ZUIYT@cim.alcatel.com.au> for stable@FreeBSD.ORG; Wed, 24 Jan 2001 07:12:28 +1100 Received: (from jeremyp@localhost) by gsmx07.alcatel.com.au (8.11.1/8.11.1) id f0NKCR462206; Wed, 24 Jan 2001 07:12:27 +1100 (EST envelope-from jeremyp) Content-return: prohibited Date: Wed, 24 Jan 2001 07:12:27 +1100 From: Peter Jeremy Subject: Re: Running with very high HZ ? In-reply-to: ; from Thierry.Herbelot@alcatel.fr on Tue, Jan 23, 2001 at 12:00:17PM +0100 To: Thierry.Herbelot@alcatel.fr Cc: stable@FreeBSD.ORG Mail-followup-to: Thierry.Herbelot@alcatel.fr, stable@FreeBSD.ORG Message-id: <20010124071227.K52423@gsmx07.alcatel.com.au> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii Content-disposition: inline User-Agent: Mutt/1.2.5i References: Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 2001-Jan-23 12:00:17 +0100, Thierry.Herbelot@alcatel.fr wrote: >more precisely : is it ok to run a recent PC (P-III + BX chipset) with >HZ=5000 ? There may be a problem with integer overflow in some tape timeout calculations at very high HZ rates. (There was a reference to it on freebsd-current recently). Other than that I don't know of any problems, though Alfred Perlstein mentioned (in mid-January) that he knew of someone who had had problems that went away when he changed HZ back to 100 - unfortunately he doesn't have any other details. I have a P-133 and a PIII-600 both running with HZ=2000 to provide reasonable accuracy with small dummynet delays. Even on the P-133, there's still negligible system/interrupt load as a result. Peter To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message