Strange Windows VM Behavior

[packinpennies]

Hi,

I have a Windows 8.1 bhyve VM that I recently spun up. I have noticed high CPU usage from even the basic system idle processes, such as Windows Update, even maxing it to 100% of the guest CPU usage. I also noticed that when I RDP to it, the CPU usage goes down, but as soon as I disconnect, it maxes out again (according to netdata).

I have given it 2 vCPUs, 4GB of RAM, a dedicated NIC igb3, and installed the virtio drivers per the steps in this post: https://forums.freenas.org/index.php?threads/freenas-11-0-rc3-windows-vm-locking-up.54986/. It gets its IP address via DHCP from my home router.

Any Linux VMs I run have no such issues. I have tried running this VM by itself with no other jails or VMs spun up.

I'm sure I'm just missing something simple here. :p What other things can I try? Thanks!

 

[wxlsxn]

My Windows VM seems to have degraded performance after upgrading from 11.1 U4 to 11.2 U1. It has almost identical resources as yours too.

 

[packinpennies]

A quick update: Per additional reading through these forums (and accidentally creating a network storm), I have since stopped using dedicated NICs for my VMs for the time being, and am bridging everything to igb0. This seems to make it perform only slightly better, but any basic apps still max the CPU in the guest.
I have also tried changing the number of vCPUs to 1 and 4, to no effect.

On my previous FreeNAS running 11.0, I haven't tried a Windows VM for comparison, but everything I've been reading suggests this is some kind of networking thing I am probably missing here.

 

[wxlsxn]

A quick update: Per additional reading through these forums (and accidentally creating a network storm), I have since stopped using dedicated NICs for my VMs for the time being, and am bridging everything to igb0. This seems to make it perform only slightly better, but any basic apps still max the CPU in the guest.
I have also tried changing the number of vCPUs to 1 and 4, to no effect.

On my previous FreeNAS running 11.0, I haven't tried a Windows VM for comparison, but everything I've been reading suggests this is some kind of networking thing I am probably missing here.

I tried changing my CPU count for the VM and I noticed regardless of which GUI I make the changes in, the guest machine does not recognize the change e.g. changing the vCPU from 2 to 4. Maybe this is indicative of a bigger issue with bhyve and the latest version of FreeNAS. I do not use a dedicated NIC and performance under 11.1 U4 was perfectly fine.

Just a quick anecdote of the performance issues; if I change a tab in Task Manager, the CPU spikes to 100%. Almost all basic tasks cause it to max out the CPU.

 

[packinpennies]

OK for your particular issue about the CPU count, there's a tunable for that I believe.

See Sean Coston's post in this thread:

https://forums.freenas.org/index.ph...rtual-cpu-assignment-issue.58034/#post-409684

My setup isn't affected by this as I'm not allocating more than 2 vCPUs though; I have 4 cores and want to retain resources for other services.

 

[wxlsxn]

OK for your particular issue about the CPU count, there's a tunable for that I believe.

See Sean Coston's post in this thread:

https://forums.freenas.org/index.ph...rtual-cpu-assignment-issue.58034/#post-409684

My setup isn't affected by this as I'm not allocating more than 2 vCPUs though; I have 4 cores and want to retain resources for other services.

Ah gotcha, well I wasn't really going to keep my setup with 4 vCPUs allocated, I was just trying to increase the vCPUs to help with performance.

 

[Frikkn]

I have encountered the same since upgrading to 11.2u1. For me pretty much everything results in high CPU usage but specifically networking and storage IO I feel are the worst. It also seems more sluggish in general, funnily enough most cpu benchmarks don't really show much difference though.

 

[wxlsxn]

Just an update, I added the two tunables as others have mentioned and my performance issues seem to be resolved.
hw.vmm.topology.cores_per_package 2 as loader
hw.vmm.topology.threads_per_core 4 as loader

https://forums.freenas.org/index.ph...h-cpu-core-on-windows-10-vm.55398/post-386790