From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751272AbWDNQYq (ORCPT ); Fri, 14 Apr 2006 12:24:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751271AbWDNQYq (ORCPT ); Fri, 14 Apr 2006 12:24:46 -0400 Received: from e5.ny.us.ibm.com ([32.97.182.145]:60581 "EHLO e5.ny.us.ibm.com") by vger.kernel.org with ESMTP id S1751268AbWDNQYp (ORCPT ); Fri, 14 Apr 2006 12:24:45 -0400 Subject: Re: [uml-devel] Re: [RFC] PATCH 0/4 - Time virtualization From: john stultz To: Jeff Dike Cc: linux-kernel@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net In-Reply-To: <20060414015316.GA7723@ccure.user-mode-linux.org> References: <200604131719.k3DHJcZG004674@ccure.user-mode-linux.org> <1144974688.8548.26.camel@cog.beaverton.ibm.com> <20060414015316.GA7723@ccure.user-mode-linux.org> Content-Type: text/plain Date: Fri, 14 Apr 2006 09:24:20 -0700 Message-Id: <1145031860.10781.6.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.4.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2006-04-13 at 21:53 -0400, Jeff Dike wrote: > On Thu, Apr 13, 2006 at 05:31:27PM -0700, john stultz wrote: > > Looks interesting. I've never quite understood the need for different > > time domains, it only allows you to run one domain with the incorrect > > time, but I'm sure there is some use case that is desired. > > There are a few possible answers - > > If when this virtualization stuff is done, no one has done anything with > time, someone is going to moan. Apparently its like painting a wall then, no? "You missed those spots over there!" :) > Once in a while, you want to fiddle your system clock to make sure that > a cron job or something does what it's supposed to. > > There was some extra infrastructure that UML needed in order to start using > this stuff, so I chose a fairly simple virtualization case to accompany it. > > > I'm not psyched about possible namespace vs nanosecond confusion w/ > > terms like "time_ns", but that's pretty minor. > > Yeah, names can be changed. Well, as long as its pretty isolated its not such a big deal. Just figured I'd bring it up as a consideration. > > Also I hope you're not wanting to deal w/ NTP adjustments between > > domains that have the incorrect time? That would be very ugly. > > No, the domain stores an offset from the system time, so it automatically > gets the system's NTP adjustments. Ok, as long as you don't intend to go down that path, these patches looks pretty harmless. thanks -john