From owner-freebsd-performance@FreeBSD.ORG Mon Jun 12 20:08:14 2006 Return-Path: X-Original-To: freebsd-performance@freebsd.org Delivered-To: freebsd-performance@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2D5A616A479 for ; Mon, 12 Jun 2006 20:08:14 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from cyrus.watson.org (cyrus.watson.org [209.31.154.42]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5C4E743D66 for ; Mon, 12 Jun 2006 20:08:13 +0000 (GMT) (envelope-from rwatson@FreeBSD.org) Received: from fledge.watson.org (fledge.watson.org [209.31.154.41]) by cyrus.watson.org (Postfix) with ESMTP id 8FA9946C58; Mon, 12 Jun 2006 16:08:12 -0400 (EDT) Date: Mon, 12 Jun 2006 21:08:12 +0100 (BST) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: Scott Long In-Reply-To: <448DC818.9070100@samsco.org> Message-ID: <20060612210723.K26068@fledge.watson.org> References: <20060612195754.72452.qmail@web33306.mail.mud.yahoo.com> <448DC818.9070100@samsco.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: freebsd-performance@freebsd.org, danial_thom@yahoo.com Subject: Re: Initial 6.1 questions X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 12 Jun 2006 20:08:14 -0000 On Mon, 12 Jun 2006, Scott Long wrote: > I run a number of high-load production systems that do a lot of network and > filesystem activity, all with HZ set to 100. It has also been shown in the > past that certain things in the network area where not fixed to deal with a > high HZ value, so it's possible that it's even more stable/reliable with an > HZ value of 100. > > My personal opinion is that HZ should gop back down to 100 in 7-CURRENT > immediately, and only be incremented back up when/if it's proven to be the > right thing to do. And, I say that as someone who (errantly) pushed for the > increase to 1000 several years ago. I think it's probably a good idea to do it sooner rather than later. It may slightly negatively impact some services that rely on frequent timers to do things like retransmit timing and the like. But I haven't done any measurements. Robert N M Watson Computer Laboratory Universty of Cambridge