From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: recurring boot time scalability issues affecting time management Date: Tue, 11 May 2010 07:59:14 +0100 Message-ID: <4BE91C62020000780000238B@vpn.id2.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org The patch titled "VT-d: prevent watchdog timer from kicking in when initializing on systems with huge amounts of memory" submitted yesterday, other than expected, fully fixed another late boot hang (when Dom0 was almost fully up), i.e. apparently unrelated to issues that may exist before Dom0 even gets started. There were no indications of time problems in any of the logs, yet there must have been such given that the boot hung without that change, but didn't with it in place. I wonder whether the time handling code in Xen itself shouldn't/can't therefore be made more robust, or at least reliably detect this sort of issue (from past analysis of similar problems, the platform timer is rolling over due to there not being frequent enough invocations of plt_overflow()) to make analysis of the problem easier. Jan