From owner-freebsd-current@FreeBSD.ORG Thu Oct 20 18:26:12 2005 Return-Path: X-Original-To: current@freebsd.org Delivered-To: freebsd-current@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 218C616A41F for ; Thu, 20 Oct 2005 18:26:12 +0000 (GMT) (envelope-from nate@root.org) Received: from www.cryptography.com (li-22.members.linode.com [64.5.53.22]) by mx1.FreeBSD.org (Postfix) with ESMTP id 966A943D62 for ; Thu, 20 Oct 2005 18:26:11 +0000 (GMT) (envelope-from nate@root.org) Received: from [10.0.0.250] (ppp-71-139-0-107.dsl.snfc21.pacbell.net [71.139.0.107]) by www.cryptography.com (8.12.8/8.12.8) with ESMTP id j9KIQ9xq017686 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); Thu, 20 Oct 2005 11:26:10 -0700 Message-ID: <4357E137.5090703@root.org> Date: Thu, 20 Oct 2005 11:25:59 -0700 From: Nate Lawson User-Agent: Mozilla Thunderbird 1.0.6 (Windows/20050716) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Alexander Leidinger References: <200510172310.j9HNAVPL013057@repoman.freebsd.org> <20051018094402.A29138@grasshopper.cs.duke.edu> <435501B9.4070401@samsco.org> <43553162.5040802@root.org> <20051020141023.0ejwdv4dss48wko0@netchild.homeip.net> In-Reply-To: <20051020141023.0ejwdv4dss48wko0@netchild.homeip.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: current@freebsd.org Subject: Re: 1kHz noise from C3 sleep X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 20 Oct 2005 18:26:12 -0000 Alexander Leidinger wrote: > Nate Lawson wrote: > > [Moving to -current] > >>> I wonder if moving to HZ=1000 on amd64 and i386 was really all that good >>> of an idea. Having preemption in the kernel means that ithreads can run >>> right away instead of having to wait for a tick, and various fixes to >>> 4BSD in the past year have eliminated bugs that would make the CPU wait >>> for up to a tick to schedule a thread. So all we're getting now is a >>> 10x increase in scheduler overhead, including reading the timecounters. >> >> >> I use hz=100 on my systems due to the 1 khz noise from C3 sleep. >> Windows has the same problem. > > > My laptop makes noises when being (more or less) idle (I think I enabled > C3...). Does this mean I should try to change HZ? Sure, you can do it from a tunable (kern.hz I think), you don't have to recompile. > If yes: Windows doesn't make such a noise, does this mean it doesn't use C3 > on this system (your comment suggests that Windows does use a HZ=1000 like > behavior)? It's possible it doesn't. Windows 2000 and newer uses hz=1000. -- Nate