From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: [timer/ticks related] dom0 hang during boot on large 1TB system Date: Mon, 21 Dec 2009 11:55:09 -0800 Message-ID: <4B2FD29D.1010807@goop.org> References: <20091221115252.2c3a64ea@mantra.us.oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20091221115252.2c3a64ea@mantra.us.oracle.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Mukesh Rathor Cc: "kurt.hackel@oracle.com" , Dan Magenheimer , "Xen-devel@lists.xensource.com" , Keir Fraser , Jan Beulich List-Id: xen-devel@lists.xenproject.org On 12/21/2009 11:52 AM, Mukesh Rathor wrote: > On Mon, 21 Dec 2009 19:07:39 +0000 > Keir Fraser wrote: > > >> On 21/12/2009 18:20, "Dan Magenheimer" >> wrote: >> >> >>> Not to say the problem can't or shouldn't be fixed in Xen. >>> Keir, would bad things happen if construct_dom0 is done after >>> scrub_heap_pages()? Other than some time wastage because >>> dom0's memory would get scrubbed just before it gets >>> overwritten (which is admittedly a much bigger problem >>> when dom0_mem is not specified in the Xen boot line >>> on a machine with ginormous memory). >>> >> The problem is more likely that Xen system time started ticking some >> time earlier during boot process. I doubt it is to do with ordering of >> construct_dom0 versus boot-time scrubbing. >> >> -- Keir >> >> > The problem is exactly how Dan described it. 'delta' for first interrupt > in dom0->timer_interrupt() goes up proportionately with amount of memory > on system. On this box, it appears more than 600GB causes delta to be > large enough to wrap jiffies. > > 1TB delta: 940b7d68a4 > 32GB delta: 02ae56eadb > > xen->send_guest_vcpu_virq() ----> dom0->handle_IRQ() -> timer_interrupt() > > timer_interrupt will call do_timer delta/NS_PER_TICK number of times. > How is it computing that delta? Anyway, I'm not at all sure this will apply to a pvops dom0 kernel as it does timekeeping quite differently from 2.6.18-xen. J