From owner-freebsd-questions@FreeBSD.ORG Thu Dec 9 05:45:39 2010 Return-Path: Delivered-To: questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 765661065673 for ; Thu, 9 Dec 2010 05:45:39 +0000 (UTC) (envelope-from modulok@gmail.com) Received: from mail-ww0-f50.google.com (mail-ww0-f50.google.com [74.125.82.50]) by mx1.freebsd.org (Postfix) with ESMTP id 0CA5E8FC0A for ; Thu, 9 Dec 2010 05:45:38 +0000 (UTC) Received: by wwf26 with SMTP id 26so1933236wwf.31 for ; Wed, 08 Dec 2010 21:45:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:cc:content-type; bh=m8Z25zUTCn/43XvPKtsZGofDrZU91BIxshA2MK7Xc7A=; b=xMFHHvsxHPfeKGhQ2zDENjwEsomjqg5/2rwpIh6M7v5AzzwAX56rvJptc3uSz7iXuL MBcr+bgLq7nY+aq9SAlj74SSdqmyVZ+fJcOpDKXj3PHi1cwuGixN5EW3wBmQcWGZYLNX YxhreqbB3MfrNXb8Wa3sKTyplnR2+NXGHVshA= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=XeaMzxpQc2eKqcdyw96+6uss1yfECCZVo3GN21yayzSrDmKIkgwKe5rijQ84+xO2CD TTZaA+Y3gKVnHYaGP2taSy/F7uZRvpZOrl+sEgV+3taIKcIaqmBtpRkWFfEw9rfNB57+ BbjoK5YxDhOJVJmDvOxCLx9ZBiPPDXGAN+wK4= MIME-Version: 1.0 Received: by 10.227.128.131 with SMTP id k3mr9916174wbs.66.1291872171709; Wed, 08 Dec 2010 21:22:51 -0800 (PST) Received: by 10.227.138.12 with HTTP; Wed, 8 Dec 2010 21:22:51 -0800 (PST) In-Reply-To: References: Date: Wed, 8 Dec 2010 22:22:51 -0700 Message-ID: From: Modulok To: Dave Cundiff Content-Type: text/plain; charset=ISO-8859-1 Cc: questions@freebsd.org Subject: Re: Terrible Clock Skew X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 09 Dec 2010 05:45:39 -0000 On 12/8/10, Dave Cundiff wrote: > Hi everyone, > > I posted this to the forum as well but figured I'd try here since the > same people might not subscribe to both. > > I've been experiencing some terrible clock skew and just can't figure > it out. By terrible I mean I'm losing 30 minutes a day. The loss only > occurs when I bring the system under heavy load. The load is multiple > Rsync backups to a ZFS pool(with gzip compression) backed by a 16 disk > Raid50. I'm using a hardware Raid controller for battery backed write > caching. > > Mobo: Supermicro X8DTL > CPU: Dual Intel 5620 quad cores > Raid: Areca 1620 > > I have ntp enabled but the skew happens to fast and it stops trying. > I've tried a bunch of stuff from the various lists. I tried all my > clock sources. TSC(-100) HPET(900) ACPI-fast(1000) i8254(0). I tried > changing the kern.hz flag lower. I also tried disabling the enhanced > speed step feature of this chip as per the FAQ on the site. Nothing > works. > > Currently I'm defaults except the following settings. > > EIST Disabled in BIOS > kern.hz="100" > kern.timecounter.hardware=i8254 > > Is there anything else I could do to debug this? I can't really blame > the hardware because I have these same boards/chips running in Linux > with no clock issues. In the man page for ntpd, you might look into "The huff-n'-puff Filter". Not saying it will help, but it seems like you've tried everything else. -Modulok-