[vfio-users] Hyperthreading and kvm

Wed Aug 19 17:35:14 UTC 2015

	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" 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
> 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>:
> >      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> 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>:
> >>>         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
> >>> > 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>:
> >>> > > 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>
> >>> 
> >>> > > 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>:
> >>> > >>> 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
> >>> > >>> https://www.redhat.com/mailman/listinfo/vfio-users