Gonglei (Arei)
2013-Jul-27 11:06 UTC
Re: [Qemu-devel] Cirrus VGA slow screen update, show blank screen last 13s or so for windows XP guest
> -----Original Message----- > From: Andreas Färber [mailto:afaerber@suse.de] > Sent: Friday, July 26, 2013 6:28 PM > To: Gerd Hoffmann; Gonglei (Arei) > Cc: Anthony Liguori; Hanweidong; Luonengjun; qemu-devel@nongnu.org; > Huangweidong (Hardware); xen-devel@lists.xen.org > Subject: Re: [Qemu-devel] Cirrus VGA slow screen update, show blank screen > last 13s or so for windows XP guest > > Am 26.07.2013 12:19, schrieb Gerd Hoffmann: > > On 07/26/13 12:02, Andreas Färber 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) > >>>> <arei.gonglei@huawei.com> wrote: > >>>>> 3. Why does the traditional qemu has no blank screen problem on cirrus > VGA > >>>> emulation ? > >>>> > >>>> This is one of the few cases where TCG is actually faster than KVM or > >>>> 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 > >>> but the upstream qemu(begin with qemu-0.14) is not for the > >>> same windows XP guest image in cirrus vga emulation. Does > >>> the cirrus vga emulation have some differences between > >>> 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. > > > > 0.14 != 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. ;)On KVM: I reproduced the issues that the VNC client show blank screen when Windows XP guest booting up from qemu-kvm-0.11.0 to latest qemu-1.5.1. I wanted to test qemu-kvm-0.10, but I didn't know the right command on it. The command beginning with qemu-kvm-0.11.0 is: ./qemu-system-x86_64 -name winXP -m 2048 -smp 2 -drive file=/mnt/sdd/image/winxp_sp3_32_2U_cn -vnc 0.0.0.0:2 -vga cirrus Hoping to help, thanks! -Gonglei> > Andreas > > -- > SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany > GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg_______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel