libvirt users - May 2023 - Windows Guest on KVM running "single core" after windows update

Hey all,

I have a Windows 10 pro (64bit) long time running as a libvirt/KVM guest that I
think Windows Update finally narfed.

The hardware is a supermicro motherboard with dual Intel E5-2640 CPUs for a
total of 40 threads and 64GB

The guest is allocated 2sockets, 5cores, 2 threads and 32GB of RAM. (I've
also tried 1 socket, 20 cores, 1 thread and 1s10c2t -- no help)

In an SSH session to the linux host (CentOS7 - up to date), htop shows 1 core
pegged and abnormal distribution of load (like it used to) even with fun little
tools in Windows like the PowerToy -> CPUStress64.exe

(i.e. the head CPU will show 90-99% and next thread in HTOP will show like 10%
which then trails off to like 5%)

Even if I tell CPUStress64.exe to load up 10 or 15 threads worth of 100%.


Has anyone else seen this?

Thanks,

 ?-Ben

> 
> I have a Windows 10 pro (64bit) long time running as a libvirt/KVM guest
> that I think Windows Update finally narfed.
> 
> The hardware is a supermicro motherboard with dual Intel E5-2640 CPUs
> for a total of 40 threads and 64GB
> 
> The guest is allocated 2sockets, 5cores, 2 threads and 32GB of RAM.
> (I've also tried 1 socket, 20 cores, 1 thread and 1s10c2t -- no help)
> 
> In an SSH session to the linux host (CentOS7 - up to date), htop shows 1
> core pegged and abnormal distribution of load (like it used to) even
> with fun little tools in Windows like the PowerToy -> CPUStress64.exe
> 
> (i.e. the head CPU will show 90-99% and next thread in HTOP will show
> like 10% which then trails off to like 5%)
> 
> Even if I tell CPUStress64.exe to load up 10 or 15 threads worth of
> 100%.
> 
I think the processor type and configuration options are most important. I am
also having win10 on el7 and weird idle load of 35%. This win10 is also
constantly writing to disk. Best is to disable al diagnostics services you do
not use. I also noticed that el9 is smoother with win10 guests, I copied the
same guest and there it is around 14%*. But if any one has an advice to get this
to levels of a linux guest doing nothing, I am very anxious to hear about it.

*not exactly same processors.