From owner-freebsd-current@FreeBSD.ORG Thu May 6 14:37:20 2004 Return-Path: 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 177F616A4CE for ; Thu, 6 May 2004 14:37:20 -0700 (PDT) Received: from odot.okladot.state.ok.us (odot.okladot.state.ok.us [192.149.244.9]) by mx1.FreeBSD.org (Postfix) with ESMTP id 7CF3C43D41 for ; Thu, 6 May 2004 14:37:19 -0700 (PDT) (envelope-from root@techpc04.okladot.state.ok.us) Received: from notes9c.okladot.state.ok.us (notes9a.okladot.state.ok.us [10.36.36.31])QAA22684; Thu, 6 May 2004 16:37:18 -0500 Received: from techpc04.okladot.state.ok.us ([199.27.9.37]) by notes9c.okladot.state.ok.us (Lotus Domino Release 5.0.12) with ESMTP id 2004050616375443:13152 ; Thu, 6 May 2004 16:37:54 -0500 Received: by techpc04.okladot.state.ok.us (Postfix, from userid 0) id 1C6C25CD1; Thu, 6 May 2004 16:36:41 -0500 (CDT) To: From: "Paul Seniura" Errors-To: "Paul Seniura" Sender: "Paul Seniura" In-Reply-To: <20040506171135.1ADEA5CB5@techpc04.okladot.state.ok.us> References: <20040506171135.1ADEA5CB5@techpc04.okladot.state.ok.us> Message-Id: <20040506213641.1C6C25CD1@techpc04.okladot.state.ok.us> Date: Thu, 6 May 2004 16:36:41 -0500 (CDT) X-MIMETrack: Itemize by SMTP Server on Notes9c/ODOT(Release 5.0.12 |February 13, 2003) at 05/06/2004 04:37:54 PM,2003) at 05/06/2004 04:37:55 PM, Serialize complete at 05/06/2004 04:37:55 PM Subject: low HZ value causes "Time Warp Bug" (re: this Puny Pentium2 suddenly became 45% slower!) X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: Paul Seniura List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 06 May 2004 21:37:20 -0000 It seems this bug happens when the HZ value goes below 16 (either by compiling 'options HZ=' in kernel or setting sysctl 'kern.hz=' in /boot/loader.conf). The computed 'ticks' value becomes too large for 2-byte int producing crazy overflowed numbers elsewhere. The crazyness extends to human clocks such as what KDE uses. I mean it was visibly speeding up and showing time to go home before it was 'really' lunchtime! Time warp!! Something needs to check for overflow, but I bet whatever this field is cannot easily be widend past 2-byte int? I guess I will file a PR on this. -- thx, Paul Seniura.