From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.91] helo=mail.sourceforge.net) by sc8-sf-list1-new.sourceforge.net with esmtp (Exim 4.43) id 1K3dGe-0007pm-5E for user-mode-linux-devel@lists.sourceforge.net; Tue, 03 Jun 2008 13:38:04 -0700 Received: from keil-draco.com ([216.193.185.50] helo=mail.keil-draco.com) by mail.sourceforge.net with esmtp (Exim 4.44) id 1K3dGc-0006QW-Gm for user-mode-linux-devel@lists.sourceforge.net; Tue, 03 Jun 2008 13:38:03 -0700 From: Daniel Hazelton Date: Tue, 3 Jun 2008 16:37:52 -0400 References: <20080603190235.GA9511@c2.user-mode-linux.org> <878wxmfg99.fsf@hades.wkstn.nix> <20080603130709.fcf6a751.akpm@linux-foundation.org> In-Reply-To: <20080603130709.fcf6a751.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Disposition: inline Message-Id: <200806031637.52992.dhazelton@enter.net> Subject: Re: [uml-devel] [PATCH 1/6] UML - Deal with host time going backwards List-Id: The user-mode Linux development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: user-mode-linux-devel-bounces@lists.sourceforge.net Errors-To: user-mode-linux-devel-bounces@lists.sourceforge.net To: Andrew Morton Cc: Nix , jdike@addtoit.com, linux-kernel@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net On Tuesday 03 June 2008 04:07:09 pm Andrew Morton wrote: > On Tue, 03 Jun 2008 20:52:18 +0100 > > Nix wrote: > > On 3 Jun 2008, Daniel Hazelton said: > > > On Tuesday 03 June 2008 03:32:11 pm Andrew Morton wrote: > > >> On Tue, 3 Jun 2008 15:02:35 -0400 > > >> > > >> Jeff Dike wrote: > > >> > Protection against the host's time going backwards - keep track of > > >> > the time at the last tick and if it's greater than the current time, > > >> > keep time stopped until the host catches up. > > >> > > >> Strange. What would cause the host's time (or at least UML's > > >> perception of it) to go backwards? > > > > > > A wild guess would be that the UML process is running "fast" at some > > > point and its expectation of the host's time is skewed forward because > > > of that. > > > > Quite so. Simply running ntp on the host (in slew-only mode, no less!) > > can cause this. > > > > > Another possibility is that the hosts clock got reset between the times > > > UML has checked it and the correction was a negative one. > > > > That too. > > So if I change the host's time by an hour, the time will not advance at all > on the guest for the next hour? Sounds suboptimal :) I agree. But like I said originally - it's a wild guess. I don't even know how accurate it is. > I suppose the guest should be running an ntp client synced to something > sane anyway? That might be helpful :) DRH -- Dialup is like pissing through a pipette. Slow and excruciatingly painful. ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel