From owner-freebsd-current@FreeBSD.ORG Mon Aug 7 19:29:28 2006 Return-Path: X-Original-To: freebsd-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 61A7E16A501 for ; Mon, 7 Aug 2006 19:29:28 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from server.baldwin.cx (66-23-211-162.clients.speedfactory.net [66.23.211.162]) by mx1.FreeBSD.org (Postfix) with ESMTP id BEC6543D62 for ; Mon, 7 Aug 2006 19:29:25 +0000 (GMT) (envelope-from jhb@freebsd.org) Received: from localhost.corp.yahoo.com (john@localhost [127.0.0.1]) (authenticated bits=0) by server.baldwin.cx (8.13.6/8.13.6) with ESMTP id k77JTN4Q036769; Mon, 7 Aug 2006 15:29:23 -0400 (EDT) (envelope-from jhb@freebsd.org) From: John Baldwin To: Jeremie Le Hen Date: Mon, 7 Aug 2006 12:43:10 -0400 User-Agent: KMail/1.9.1 References: <20060529153103.GA17178@obiwan.tataz.chchile.org> <200606011441.07494.jhb@freebsd.org> <20060805090119.GM4498@obiwan.tataz.chchile.org> In-Reply-To: <20060805090119.GM4498@obiwan.tataz.chchile.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200608071243.10476.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH authentication, not delayed by milter-greylist-2.0.2 (server.baldwin.cx [127.0.0.1]); Mon, 07 Aug 2006 15:29:23 -0400 (EDT) X-Virus-Scanned: ClamAV 0.87.1/1639/Mon Aug 7 09:34:09 2006 on server.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-4.4 required=4.2 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.1.0 X-Spam-Checker-Version: SpamAssassin 3.1.0 (2005-09-13) on server.baldwin.cx Cc: freebsd-current@freebsd.org Subject: Re: [fbsd] Re: [fbsd] timer goes sluggish 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: Mon, 07 Aug 2006 19:29:28 -0000 On Saturday 05 August 2006 05:01, Jeremie Le Hen wrote: > Hi John, > > On Thu, Jun 01, 2006 at 02:41:07PM -0400, John Baldwin wrote: > > On Tuesday 30 May 2006 18:32, Jeremie Le Hen wrote: > > > Hi, > > > > > > On Mon, May 29, 2006 at 05:31:03PM +0200, Jeremie Le Hen wrote: > > > > Hi, > > > > > > > > I won't write too much, the following session will tell much more: > > > > > > > > % jarjarbinks:root# ntpdate -b chronos.cru.fr > > > > % 29 May 17:08:44 ntpdate[4254]: step time server 195.220.94.163 offset > > 0.000273 sec > > > > % jarjarbinks:root# sysctl kern.timecounter.hardware > > > > % kern.timecounter.hardware: ACPI-fast > > > > % jarjarbinks:root# while : ; do date ; sleep 1 ; done > > > > % Mon May 29 17:08:56 CEST 2006 > > > > % Mon May 29 17:09:03 CEST 2006 > > > > % Mon May 29 17:09:09 CEST 2006 > > > > % Mon May 29 17:09:16 CEST 2006 > > > > % Mon May 29 17:09:22 CEST 2006 > > > > % ^C > > > > > > Sometimes, I feel dumb. > > > > > > I noticed that the clock sped up when the CPU makes heavy computing, > > > which meant there was some power saving on idleness. > > > > > > I dug a bit I found that hw.acpi.cpu.cx_lowest=C4. > > > Setting it hw.acpi.cpu.cx_lowest=C1 makes the clock goes ``in time'' :). > > > > If you are using APIC, try disabling APIC and see if it works ok with higher > > Cx states. > > Sorry for the delay. > > I was indeed using APIC, and got a chance to disable it. I am writing > this mail with C4 state set and it works flawlessly: > > % # sysctl hw.acpi.cpu.cx_lowest > % hw.acpi.cpu.cx_lowest: C4 > % # while : ; do date ; sleep 1 ; done > % Sat Aug 5 10:54:19 UTC 2006 > % Sat Aug 5 10:54:20 UTC 2006 > % Sat Aug 5 10:54:21 UTC 2006 > % Sat Aug 5 10:54:22 UTC 2006 > > > What's the point in disabling apic ? Am I supposed to lose some > features along with the apic support removal, or is it something I > won't notice ? On a laptop you probably won't notice unless it is a dual-core CPU or one with HT (and you want to use the HT) as disabling APIC disables support for SMP on x86. -- John Baldwin