[vfio-users] Hyperthreading and kvm

Sat Aug 22 17:19:43 UTC 2015

Just to add, I don’t believe Cirrus is deprecated, but qxl is definitely better from a performance standpoint (at least that’s what I noticed from my testing).  QXL also works the same with OVMF and SeaBIOS.  Cirrus works with OVMF, but I have issues trying to use vmvga with OVMF.  The latest virtio drivers ISO also has the WDDM drivers for QXL for Windows 8 and above, allowing you to have better control over resolution in the guest as well as better performance.  Generally speaking, QXL seems to be the real winner for virtual graphics in my book.

Now how to pass that as a qemu string?  Not really sure because I use libvirt for everything.

> On Aug 22, 2015, at 12:11 PM, Blank Field <ihatethisfield at gmail.com> wrote:
> 
> >-vga cirrus
> ...
> dude.
> You need QXL-VGA. Cirrus is.. deprecated, i think.
> 
> 2015-08-22 20:02 GMT+03:00 José Ramón Muñoz <koalinux at gmail.com <mailto:koalinux at gmail.com>>:
>         Hi,
> 
>         I gave it a try today with no success. The launch command was:
> 
> /qemu-system-x86_64 -enable-kvm -vga cirrus -cpu host -smp 4,cores=4,threads=1
> -m 4096 \
>         -netdev user,id=user.0 -device e1000,netdev=user.0 \
>         -usb -usbdevice tablet \
>         -drive if=pflash,format=raw,readonly,file=/usr/share/edk2.git/ovmf-
> x64/OVMF_CODE-with-csm.fd \
>         -drive if=pflash,format=raw,file=/usr/share/edk2.git/ovmf-
> x64/Windows_ovmf_vars_x64.fd \
>         -drive
> file=/dev/koalita/koalitavm,format=raw,cache=none,aio=native,if=virtio
> 
>         I tried to launch it using the virtio disk, the ide disk, and empty disk
> with the windows 7 installer, and even without disk to see if the cdrom
> launchs ok.
> 
>         Best regards.
> 
>         José.
> 
> On Wednesday 19 August 2015 23:23:43 Blank Field wrote:
> > The need of Q35 is overrated. Usually you need it for booting from sata
> > controllers or something.
> > For our use 440fx works better.
> > I've used windows 7 on my machine. All you need to do is to follow the OVMF
> > whitepaper:
> > http://www.linux-kvm.org/downloads/lersek/ovmf-whitepaper-c770f8c.txt <http://www.linux-kvm.org/downloads/lersek/ovmf-whitepaper-c770f8c.txt>
> >
> > 2015-08-19 20:35 GMT+03:00 José Ramón Muñoz <koalinux at gmail.com <mailto:koalinux at gmail.com>>:
> > >         Hi,
> > >
> > >         Sorry for not replying to all, I wrote from the phone and
> > >         sometimes
> > >
> > > happens.
> > >
> > >         About the ovmf stuff, I would give it a try just in case I didn't
> > >
> > > read the
> > > Alex Williamson post that explained that I need windows > win7 to be able
> > > to
> > > use it. I'm still not planning to upgrade it to windows 10.
> > >
> > >         How about q35? I tried to launch it but it seems to yield a
> > >
> > > beautiful
> > > BSOD because of the ati drivers not being expanded. Do anyone uses it
> > > regularly?
> > >
> > >         BR.
> > >
> > >         José.
> > >
> > > On Wednesday 19 August 2015 20:12:23 Blank Field wrote:
> > > > Please, use the reply-all button. Include "vfio-users at redhat.com <mailto:vfio-users at redhat.com>"
> > >
> > > address
> > >
> > > > in the "to:" field.
> > > >
> > > > >    So, I got it right that using OVMF my setup can work reliably? I
> > > > >    was
> > > >
> > > > considering to build it but it seems to be not so straight forward in
> > > > Gentoo.
> > > >
> > > > I haven't tried doing this on gentoo, but you can try using "alien" to
> > >
> > > use
> > >
> > > > RPMs from kraxel.org <http://kraxel.org/>
> > > > https://www.kraxel.org/repos/ <https://www.kraxel.org/repos/>
> > > > Also, i recall there was just plain binary files builds from jenkins,
> > >
> > > lurk
> > >
> > > > around and see if you can make yourself an ebuild with an overlay.
> > > > Also, there's a xen-tools package which has OVMF USE-flag, try
> > >
> > > researching
> > >
> > > > this.
> > > > And i think i saw an user-created portage overlay with the OVMF package
> > >
> > > in
> > >
> > > > there.
> > > >
> > > > I think plain libvirt and virt-manager should already be in the main
> > > > portage tree.
> > > >
> > > > 2015-08-19 6:16 GMT+03:00 José Ramón Muñoz Pekkarinen <
> > >
> > > koalinux at gmail.com <mailto:koalinux at gmail.com>>:
> > > > >      Hi,
> > > > >
> > > > >     So, I got it right that using OVMF my setup can work reliably? I
> > >
> > > was
> > >
> > > > > considering to build it but it seems to be not so straight forward in
> > > > > Gentoo.
> > > > >
> > > > >     BR.
> > > > >
> > > > >     José
> > > > >
> > > > > On Aug 19, 2015 3:09 AM, "Blank Field" <ihatethisfield at gmail.com <mailto:ihatethisfield at gmail.com>>
> > >
> > > wrote:
> > > > >> Well, that sounds like the first time i've got it working.
> > > > >> Sooo, i've managed to make it work back then with just x-vga and
> > > > >> qemu.
> > > > >> It worked. Sometimes.
> > > > >> Sometimes it crashed the host.
> > > > >> Sometimes it froze the VM and messed up the GPU.
> > > > >> I did a foolish research with no results whatsoever, but i've made
> > > > >> one
> > > > >> observation - if the firefox is started and it eats a ton of memory,
> > > > >> i
> > > > >> have
> > > > >> better chances to run the VM right.
> > > > >> However, i've dropped that way and went the OVMF way, avoiding the
> > >
> > > VGA.
> > >
> > > > >> Check the dmesg, maybe you're more lucky than me with the motherboard
> > >
> > > and
> > >
> > > > >> it's just the GPU that freezes. Also, i'd check the temperatures.
> > > > >>
> > > > >> 2015-08-19 0:25 GMT+03:00 José Ramón Muñoz <koalinux at gmail.com <mailto:koalinux at gmail.com>>:
> > > > >>>         Hi,
> > > > >>>
> > > > >>>         I'm using and APU a8-7650k, and apart that from time to time
> > >
> > > the
> > >
> > > > >>> win7
> > > > >>> guest decides to freeze, so many times during boot time, and
> > > > >>> ocassionally
> > > > >>> during gaming, I'm fairly happy with the performance. The passed
> > >
> > > through
> > >
> > > > >>> gpu
> > > > >>> is a HD5670 and I managed to play games like MGS Ground Zeroes,
> > >
> > > Blades
> > >
> > > > >>> of
> > > > >>> times, and currently DAO: Origins.
> > > > >>>
> > > > >>>         Best regards.
> > > > >>>
> > > > >>>         José.
> > > > >>>
> > > > >>> On Wednesday 19 August 2015 00:09:09 Blank Field wrote:
> > > > >>> > Use "Reply All" button. Include the mailing list in the "to:"
> > >
> > > field.
> > >
> > > > >>> > >I'm currently running an A10-5700 with a discrete Nvidia card,
> > > > >>> > >and
> > > > >>>
> > > > >>> I've
> > > > >>>
> > > > >>> > got a LMDE2 install in which I'm preparing to do an experimental
> > >
> > > W10
> > >
> > > > >>> VM.
> > > > >>>
> > > > >>> > So, according to your experience, I shouldn't expect much with
> > > > >>> > this
> > > > >>> > processor, then?
> > > > >>> > http://pastebin.com/rEhebfQM <http://pastebin.com/rEhebfQM>
> > > > >>> > It will work. But it has taken a year for me to figure out how to
> > >
> > > make
> > >
> > > > >>> it
> > > > >>>
> > > > >>> > work.
> > > > >>> > The pastebin link is my currently working domain xml.
> > > > >>> > Two asus HD7750 on an asus F2A55+Athlon X4 750k (Trinity).
> > > > >>> > The kernel and module parameters are:
> > > > >>> > options kvm-amd npt=1 nested=0
> > > > >>> > options kvm ignore_msrs=0 allow_unsafe_assigned_interrupts=0
> > > > >>> > options vfio_iommu_type1 disable_hugepages=1
> > >
> > > allow_unsafe_interrupts=0
> > >
> > > > >>> > CMDLINE:
> > > > >>> > nofb pci-stub.ids=1022:780d,1002:683f,1002:aab0
> > > > >>> > enable_mtrr_cleanup
> > > > >>> > amd_iommu_dump=1 iommu=pt acpi_enforce_resources=lax
> > > > >>> >
> > > > >>> > Try doing it with nested=1
> > > > >>> >
> > > > >>> > If you will use libvirt, that should work 100%, as i have almost
> > >
> > > the
> > >
> > > > >>> same
> > > > >>>
> > > > >>> > CPU.
> > > > >>> >
> > > > >>> > 2015-08-18 23:57 GMT+03:00 ALG Bass <olorin12 at gmail.com <mailto:olorin12 at gmail.com>>:
> > > > >>> > > Gotcha. So it would be better if I got the i7.
> > > > >>> > > I'm currently running an A10-5700 with a discrete Nvidia card,
> > >
> > > and
> > >
> > > > >>> I've
> > > > >>>
> > > > >>> > > got a LMDE2 install in which I'm preparing to do an experimental
> > >
> > > W10
> > >
> > > > >>> VM.
> > > > >>>
> > > > >>> > > So, according to your experience, I shouldn't expect much with
> > >
> > > this
> > >
> > > > >>> > > processor, then?
> > > > >>> > >
> > > > >>> > > On Tue, Aug 18, 2015 at 3:46 PM, Blank Field <
> > > > >>>
> > > > >>> ihatethisfield at gmail.com <mailto:ihatethisfield at gmail.com>>
> > > > >>>
> > > > >>> > > wrote:
> > > > >>> > >> Hyperthreading on host means MORE cores which you can commit to
> > >
> > > the
> > >
> > > > >>> VM.
> > > > >>>
> > > > >>> > >> More cores = more performance.
> > > > >>> > >> It is good for you.
> > > > >>> > >> For the host it doesn't matter logical or physical. For the VM,
> > > > >>>
> > > > >>> you'd
> > > > >>>
> > > > >>> > >> want to pin "pairs" of cores, so there would be less CPU cache
> > > > >>>
> > > > >>> issues.
> > > > >>>
> > > > >>> > >> Like, assign a core and it's sibling instead of two separate
> > >
> > > cores.
> > >
> > > > >>> > >> I use AMD Athlon X4 750k which is based off A10-5700, and it's
> > > > >>>
> > > > >>> working
> > > > >>>
> > > > >>> > >> very unstable.
> > > > >>> > >> The only way to get it working - use OVMF without VGA and do
> > > > >>> > >> not
> > > > >>> > >> use
> > > > >>> > >> hugepages.
> > > > >>> > >> That's all.
> > > > >>> > >>
> > > > >>> > >> P.S.
> > > > >>> > >> Oh well, here we go again.
> > > > >>> > >>
> > > > >>> > >> 2015-08-18 22:26 GMT+03:00 ALG Bass <olorin12 at gmail.com <mailto:olorin12 at gmail.com>>:
> > > > >>> > >>> Hi all, new to this list, kvm, and vfio. I've been researching
> > > > >>>
> > > > >>> this for
> > > > >>>
> > > > >>> > >>> about a week.
> > > > >>> > >>> I'm also going to be building a computer in the near future,
> > > > >>> > >>> so
> > > > >>>
> > > > >>> I've got
> > > > >>>
> > > > >>> > >>> a quick two part question:
> > > > >>> > >>> Does the hyperthreading on i7 series Intel processors make a
> > > > >>>
> > > > >>> significant
> > > > >>>
> > > > >>> > >>> difference in running Windows in a VM, such that it's a
> > >
> > > noticeable
> > >
> > > > >>> > >>> increase
> > > > >>> > >>> in performance over an i5? And, does anyone here run Windows
> > >
> > > in a
> > >
> > > > >>> VM
> > > > >>>
> > > > >>> > >>> using
> > > > >>> > >>> an AMD A-series APU like the 7700k, and how is the
> > > > >>> > >>> performance?
> > > > >>> > >>>
> > > > >>> > >>> Thank you!
> > > > >>> > >>>
> > > > >>> > >>> _______________________________________________
> > > > >>> > >>> vfio-users mailing list
> > > > >>> > >>> vfio-users at redhat.com <mailto:vfio-users at redhat.com>
> > > > >>> > >>> https://www.redhat.com/mailman/listinfo/vfio-users <https://www.redhat.com/mailman/listinfo/vfio-users>
> 
> 
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