From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rik van Riel Subject: Re: [RFC 2/7] change headers preparing for steal time Date: Thu, 26 Aug 2010 18:11:54 -0400 Message-ID: <4C76E6AA.9020405@redhat.com> References: <1282772597-4183-1-git-send-email-glommer@redhat.com> <1282772597-4183-2-git-send-email-glommer@redhat.com> <1282772597-4183-3-git-send-email-glommer@redhat.com> <4C76D22D.9010007@redhat.com> <4C76D6C2.3010608@redhat.com> <20100826211743.GF2985@mothafucka.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Zachary Amsden , kvm@vger.kernel.org, avi@redhat.com, mtosatti@redhat.com To: Glauber Costa Return-path: Received: from mx1.redhat.com ([209.132.183.28]:57894 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753127Ab0HZWL7 (ORCPT ); Thu, 26 Aug 2010 18:11:59 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o7QMBxXl027623 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 26 Aug 2010 18:11:59 -0400 In-Reply-To: <20100826211743.GF2985@mothafucka.localdomain> Sender: kvm-owner@vger.kernel.org List-ID: On 08/26/2010 05:17 PM, Glauber Costa wrote: > On Thu, Aug 26, 2010 at 05:04:02PM -0400, Rik van Riel wrote: >> On 08/26/2010 04:44 PM, Zachary Amsden wrote: >>> Will 32 bits be enough? >> >> Good question. Reading the rest of the code, >> I suspect it won't be, but Glauber will know >> better. > > We are at msec resolution, not nanoseconds. > And I doubt we need more than that, since > we'll later on convert to jiffie granularity. > > it gives us enough for about 50 days of steal > time. I guess what really helps us here is that kvm_get_steal_time() returns the delta. This means it can be (it's using u64 at the moment, but that is fixable) changed to deal with overflows. At that point, it should do the right thing even if the 32 bit value contained nanoseconds. And with microseconds, it would certainly be plenty :) -- All rights reversed