From owner-freebsd-questions@FreeBSD.ORG Tue Sep 13 10:21:45 2011 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 7BD8E106564A for ; Tue, 13 Sep 2011 10:21:45 +0000 (UTC) (envelope-from brett@lariat.net) Received: from lariat.net (lariat.net [66.62.230.51]) by mx1.freebsd.org (Postfix) with ESMTP id 1B9F18FC0A for ; Tue, 13 Sep 2011 10:21:44 +0000 (UTC) Received: from WildRover.lariat.net (IDENT:ppp1000.lariat.net@lariat.net [66.119.58.2] (may be forged)) by lariat.net (8.9.3/8.9.3) with ESMTP id EAA26090; Tue, 13 Sep 2011 04:21:36 -0600 (MDT) Message-Id: <201109131021.EAA26090@lariat.net> X-Mailer: QUALCOMM Windows Eudora Version 7.1.0.9 Date: Tue, 13 Sep 2011 04:21:39 -0600 To: Adam Vande More From: Brett Glass In-Reply-To: References: <201109122350.RAA21916@lariat.net> <201109130443.WAA23650@lariat.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: questions@freebsd.org Subject: Re: Negative ping times with FreeBSD 8.1-RELEASE on older Celeron system 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: Tue, 13 Sep 2011 10:21:45 -0000 Thank you! Since it's tunable at runtime I just tested it, and -- sure enough -- no negative ping times. Ironically, it was the kernel that selected the ACPI timer, scoring it higher than the timestamp counter as a clock source. Perhaps code should be added to ensure that the timer is not chosen if it rolls over in less than a second, since this clearly leads to imprecision and missed rollovers. --Brett Glass At 11:04 PM 9/12/2011, Adam Vande More wrote: >it's a runtime tunable so /etc/sysctl.conf