From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:57473) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TkcCO-0006DS-6K for qemu-devel@nongnu.org; Mon, 17 Dec 2012 10:01:45 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TkcCN-00034f-3q for qemu-devel@nongnu.org; Mon, 17 Dec 2012 10:01:44 -0500 Received: from mx1.redhat.com ([209.132.183.28]:34574) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TkbrC-0005gN-DT for qemu-devel@nongnu.org; Mon, 17 Dec 2012 09:39:50 -0500 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 (8.14.4/8.14.4) with ESMTP id qBHEdnnr026627 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 17 Dec 2012 09:39:49 -0500 Message-ID: <50CF2EB3.9020501@redhat.com> Date: Mon, 17 Dec 2012 15:39:47 +0100 From: Gerd Hoffmann MIME-Version: 1.0 References: <1355492147-5023-1-git-send-email-hdegoede@redhat.com> <1355492147-5023-10-git-send-email-hdegoede@redhat.com> <50CF1B33.7060708@redhat.com> <50CF2AFB.2050705@redhat.com> In-Reply-To: <50CF2AFB.2050705@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 09/26] ehci: Use uframe precision for interrupt threshold checking List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Hans de Goede Cc: qemu-devel@nongnu.org On 12/17/12 15:23, Hans de Goede wrote: > Hi, > > On 12/17/2012 02:16 PM, Gerd Hoffmann wrote: >> On 12/14/12 14:35, Hans de Goede wrote: >>> Note that a shadow variable is used instead of changing frindex to >>> uframe accuracy because we must send a frindex which is a multiple of 8 >>> during migration for migration compatibility, and rounding it down to >>> a multiple of 8 pre-migration, can lead to frindex going backwards from >>> the guest pov. >> >> Jumping forward instead? > > You mean rounding the send frindex up pre-migration, I didn't really > consider > that as it will cause us skipping processing an entry in the periodic frame > list. I guess doing that on migration isn't too bad. OTOH giving the guest > only frame accuracy like we've been doing till now also works fine... > > Your choice :) I'm looking for a way to avoid the shadow variable, but of course without breaking migration. giving the guest only frame accuracy looks good to me. cheers, Gerd