On 2012-02-01 16:43, Erik Rull wrote: > On February 1, 2012 at 3:42 PM Jan Kiszka <jan.kiszka@xxxxxxxxxxx> wrote: > >> On 2012-02-01 15:02, Erik Rull wrote: >>> >>> On February 1, 2012 at 2:40 PM Avi Kivity <avi@xxxxxxxxxx> wrote: >>> >>>> On 02/01/2012 02:52 PM, Erik Rull wrote: >>>>> Hi all, >>>>> >>>>> first of all I'm a bit confused: >>>>> >>>>> What is the difference between qemu with command line option >>> --enable-kvm >>>>> and qemu-kvm? >>>>> It seems to be a difference in code so far, from the performance > point >>> of >>>>> view it seems to be the same... >>>> >>>> The differences are being reduced rapidly, thanks to Jan's efforts. >>>> Right now what remains is PIT performance and accuracy, device >>>> assignment, and Windows XP performance. Most guests should see the > same >>>> performance. >> >> MSI performance is expected to be worse with upstream as well, thus > virtio. >> >>>> >>>>> Now my issue that lead me to a git bisect on qemu-kvm: >>>>> The following commit / merge breaks my windows guest boot sequence > and >>>>> causes resets infinitely: >>>>> ec757c67c40a56492001487e69272f62144fd124 Merge branch > 'upstream-merge' >>> into >>>>> next So commit aad3b517a1b83561f2755dc4451596a421399c19, i.e. the last merge before that one is still fine? >>>>> Thu, 5 Jan 2012 11:00:07 +0000 (13:00 +0200) Avi Kivity >>> <avi@xxxxxxxxxx> >>>>> >>>>> >>>>> Interesting: qemu with --enable-kvm master and the same command line >>>>> options as qemu-kvm runs perfect. >>>>> My command line options are: >>>>> qemu-system-x86_64 -serial /dev/ttyS2 -readconfig >>> /etc/ich9-ehci-uhci.cfg >>>>> -device usb-host,bus=ehci.0 -device usb-tablet -drive >>>>> file=/dev/sda2,cache=off -m 1024 -net nic,macaddr=$MACADDR -net >>>>> tap,script=/etc/qemu-ifup -no-acpi -monitor stdio -L >>> /usr/X11R6/share/qemu >>>>> -boot c -localtime >>>>> >>>>> >>>> >>>> What version of Windows are you using? What's the contents of >>>> /etc/ich9-ehci-uhci.cfg? >>>> >>> >>> Hi Avi, >>> >>> the contents from the .cfg are located in docs/ich9-ehci-uhci.cfg >>> >>> I tried two versions of Windows XP: One is the default Windows XP SP3 > that >>> you get from MSDN, one is Windows Embedded Standard (embedded > customized >>> XP). >>> >>> Both show the same behavior: boots with qemu -enable-kvm and > continuously >>> reboots with qemu-kvm. >> >> What does qemu-kvm with -no-kvm-irqchip do? >> >> Jan >> > > Wow - that works! > Does this influence the guest performance? > Yes, how much depends on your workload. Still strange, though. We should try to understand this issue. It stays like this up to and including current qemu-kvm.git master? Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
