[vfio-users] Users of X99-boards, can you do me a small favor?

Brett Peckinpaugh bp10 at erylflynn.com
Tue Oct 4 16:32:02 UTC 2016

What are you settling that fixes the Nvidia experience complaint? 

On October 4, 2016 9:15:56 AM PDT, Hristo Iliev <hristo at hiliev.eu> wrote:
>Hi Martin,
>Am 04.10.2016 10:09, schrieb Martin Schrodt:
>> Hi Hristo,
>>> No need to sleep/wake - my X99-based system starts with TSC
>>> $ dmesg | grep TSC
>>> [    0.000000] tsc: Fast TSC calibration using PIT
>>> [    0.077986] TSC deadline timer enabled
>>> [    0.203383] TSC synchronization [CPU#0 -> CPU#1]:
>>> [    0.203384] Measured 974558547804462 cycles TSC warp between
>>> turning off TSC clock.
>>> [    0.203388] tsc: Marking TSC unstable due to
>>> failed
>>> Consequently, tsc is not among the clock sources listed in
>>> available_clocksource. KVM is not happy about that:
>>> [16739.200656] kvm: SMP vm created on host with unstable TSC; guest 
>>> TSC
>>> will not be reliable
>> Ok, so an X99-board that behaves like this even on a fresh start.
>> Interesting.
>>> But I haven't observed any instabilities of the Windows 10 guest, 
>>> which
>>> happily runs with 4 virtual CPUs (2 virtual hyperthreaded CPUs)
>>> to
>>> two cores of my i7-5820K.
>> This really makes me think there's something else involved in this
>> behaviour. Maybe the CPU configuration (I use "Skylake-Client")
>> TSC to the guest, so if you put that on, it'll use it?
>> Can you check what kind of virtual CPU you use?
>I use 'passthrough', otherwise the default 'Haswell-noTSX' that 
>virt-manager picks results in NVIDIA GeForce Experience complaining 
>about unrecognised CPU type, so the TSC gets pretty much exposed to the
>Just found this paste with a boot log from another system with the same
>motherboard, though with an older BIOS version and a Xeon E5-1620 v3 
>It shows the same problem with unsynchronised TSCs. Could also be 
>something specific to the LGA 2011v3 processors or to the EFI BIOS.
>take a look in the BIOS options when time permits.
>> Cheers,
>> Martin
>vfio-users mailing list
>vfio-users at redhat.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/vfio-users/attachments/20161004/8f57335d/attachment.htm>

More information about the vfio-users mailing list