From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38293) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V2fFH-0001o6-I8 for qemu-devel@nongnu.org; Fri, 26 Jul 2013 06:27:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V2fFG-0007Zn-HZ for qemu-devel@nongnu.org; Fri, 26 Jul 2013 06:27:35 -0400 Received: from cantor2.suse.de ([195.135.220.15]:51748 helo=mx2.suse.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V2fFG-0007Zi-8b for qemu-devel@nongnu.org; Fri, 26 Jul 2013 06:27:34 -0400 Message-ID: <51F24F12.7050503@suse.de> Date: Fri, 26 Jul 2013 12:27:30 +0200 From: =?UTF-8?B?QW5kcmVhcyBGw6RyYmVy?= MIME-Version: 1.0 References: <33183CC9F5247A488A2544077AF190207EF6A7E6@szxeml538-mbx.china.huawei.com> <33183CC9F5247A488A2544077AF190207EF6BEC3@szxeml538-mbx.china.huawei.com> <33183CC9F5247A488A2544077AF190207EF6BF06@szxeml538-mbx.china.huawei.com> <51F24949.4070109@suse.de> <51F24D24.4020201@redhat.com> In-Reply-To: <51F24D24.4020201@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] Cirrus VGA slow screen update, show blank screen last 13s or so for windows XP guest List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerd Hoffmann , "Gonglei (Arei)" Cc: Hanweidong , Luonengjun , "qemu-devel@nongnu.org" , "xen-devel@lists.xen.org" , Anthony Liguori , "Huangweidong (Hardware)" Am 26.07.2013 12:19, schrieb Gerd Hoffmann: > On 07/26/13 12:02, Andreas F=C3=A4rber wrote: >> Am 26.07.2013 08:41, schrieb Gonglei (Arei): >>>> -----Original Message----- >>>> From: Anthony Liguori [mailto:anthony@codemonkey.ws] >>>> Sent: Friday, July 26, 2013 11:21 AM >>>> To: Gonglei (Arei) >>>> Cc: qemu-devel@nongnu.org; xen-devel@lists.xen.org; Hanweidong; >>>> Luonengjun; Huangweidong (Hardware) >>>> Subject: Re: [Qemu-devel] Cirrus VGA slow screen update, show blank = screen >>>> last 13s or so for windows XP guest >>>> >>>> On Thu, Jul 25, 2013 at 10:08 PM, Gonglei (Arei) >>>> wrote: >>>>> 3. Why does the traditional qemu has no blank screen problem on cir= rus VGA >>>> emulation ? >>>> >>>> This is one of the few cases where TCG is actually faster than KVM o= r >>>> Xen. In TCG, an MMIO exit is converted to a function call. OTOH, >>>> even with KVM, an MMIO exit is at least a couples thousand cycles. >>>> It's worse with Xen because dom0 has to be scheduled. >>> >>> Perhaps I did not express clearly what I mean at #3. >>> I don't understand why the qemu-dm(qemu-0.10.2) works well=20 >>> but the upstream qemu(begin with qemu-0.14) is not for the=20 >>> same windows XP guest image in cirrus vga emulation. Does=20 >>> the cirrus vga emulation have some differences between=20 >>> qemu-dm and unstream qemu ? >> >> I don't know about qemu-dm, but QEMU switched from a home-grown pixel >> handling to pixman library sometime around 1.4. CC'ing Gerd. >=20 > 0.14 !=3D 1.4 ;) Oops! In that case, Gonglei, try to reproduce the issue with upstream 0.10 and use git-bisect to find out when things got slower between v0.10.2..v0.14.0. It would be unrealistic to expect us to remember all Cirrus-related changes from 2-4 years ago. ;) Andreas --=20 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=C3=BCrnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imend=C3=B6rffer; HRB 16746 AG N=C3=BC= rnberg