From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34116) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VEfaM-0006NZ-4n for qemu-devel@nongnu.org; Wed, 28 Aug 2013 09:15:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VEfaG-0004uA-4F for qemu-devel@nongnu.org; Wed, 28 Aug 2013 09:14:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:21923) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VEfaF-0004u3-SX for qemu-devel@nongnu.org; Wed, 28 Aug 2013 09:14:52 -0400 Message-ID: <521DF7C1.50805@redhat.com> Date: Wed, 28 Aug 2013 15:14:41 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <586568842.455717.1377510746935.open-xchange@email.1und1.de> <20130827073833.GB24247@stefanha-thinkpad.redhat.com> <521D0B84.8040301@rdsoftware.de> <521D1AB0.1070904@redhat.com> <20130828075020.GA4696@stefanha-thinkpad.muc.redhat.com> <163348110.541056.1377680875692.open-xchange@email.1und1.de> In-Reply-To: <163348110.541056.1377680875692.open-xchange@email.1und1.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] Boot Problems Windows XP guest List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Erik Rull Cc: Stefan Hajnoczi , "qemu-devel@nongnu.org" , =?UTF-8?B?QmVub8OudCBDYW5ldA==?= Il 28/08/2013 11:07, Erik Rull ha scritto: >>> It could be a real difference, actually. An unexpectedly fast disk >>> might screw a sloppy driver. IIRC you're not the first person reporting >>> it. Stefan, do you think using block throttling could fix it (with some >>> trial and error)? >> >> That might work. You could start with something like -drive ...,iops=20 >> and then disable the limit from the QEMU monitor once the guest OS is >> booting (block_set_io_throttle virtio0 0 0 0 0 0 0). >> >> It would be easier to try -drive ...,cache=writethrough and -win2k-hack >> first as Anthony suggests. >> >> Stefan > > Thanks. > I tried that, but when should I reset the throttle? Never. The bug will be there through the whole execution of the guest. > When I reset it some seconds > after the BIOS screen disappeared same result as without throttling. When I keep > it, Windows still reboots, the cycle just takes longer (half an hour), but the > progress seems to be the same as without throttle. On second thought that is expected. Until throttling kicks in, I/O will complete just as fast as without throttling. Maybe limiting the number of bytes per second instead of I/O ops would be better. Can you try -drive ...,bps=1048576 (possibly higher or lower numbers too)? And maybe Benoit's new algorithm could help too. Benoit, do you have a tree for Erik to try? Paolo