Low CPU Frequency in guests

[Yazik]

Hello!
I have Supermicro server with Intel Xeon Gold 5220R CPU. I setup max performance settings for CPU in BIOS and disable P-State, C-State and other options for power saving.
On PVE-host i have 4000 MHz freq - it's turbo boost. I have governor on performance.
But in my guests VM's i have only 1400 MHz
My debian guest cfg:

agent: 1
boot: order=scsi0;net0
cores: 24
cpu: host
memory: 57344
meta: creation-qemu=8.1.5,ctime=1710497635
name: postgres-debian
net0: virtio=BC:24:11:97:5B:99,bridge=vmbr0
numa: 1
ostype: l26
scsi0: raid10-nvme:101/vm-101-disk-0.raw,discard=on,iothread=1,size=600G,ssd=1
scsi1: raid10-ssd:101/vm-101-disk-0.raw,cache=writeback,discard=on,iothread=1,size=80G,ssd=1
scsihw: virtio-scsi-single
smbios1: uuid=2cc16871-2256-4782-bffe-8852d87ce4cf
sockets: 1

Win guest

agent: 1
balloon: 0
bios: ovmf
boot: order=scsi0;ide0;net0
cores: 24
cpu: host
efidisk0: raid10-nvme:100/vm-100-disk-0.qcow2,efitype=4m,pre-enrolled-keys=1,size=528K
machine: pc-q35-8.1
memory: 65536
meta: creation-qemu=8.1.5,ctime=1710497541
name: 1c
net0: virtio=BC:24:11:5B:84:60,bridge=vmbr0
numa: 1
ostype: win11
scsi0: raid10-nvme:100/vm-100-disk-1.raw,cache=writeback,discard=on,iothread=1,size=320G,ssd=1
scsi1: raid10-ssd:100/vm-100-disk-0.raw,cache=writeback,iothread=1,size=80G,ssd=1
scsihw: virtio-scsi-single
smbios1: uuid=a5f0ce3b-2903-4f6f-b641-4f32251d0d43
sockets: 1
tpmstate0: raid10-nvme:100/vm-100-disk-2.raw,size=4M,version=v2.0

I read on forum about vm's see only base clock of CPU. But base frequency of Gold 5220R - 2200 MHz. What wrong?

pveversion -v
proxmox-ve: 8.1.0 (running kernel: 6.5.13-1-pve)
pve-manager: 8.1.4 (running version: 8.1.4/ec5affc9e41f1d79)
proxmox-kernel-helper: 8.1.0
proxmox-kernel-6.5.13-1-pve-signed: 6.5.13-1
proxmox-kernel-6.5: 6.5.13-1
ceph-fuse: 16.2.11+ds-2
corosync: 3.1.7-pve3
criu: 3.17.1-2
glusterfs-client: 10.3-5
ifupdown: residual config
ifupdown2: 3.2.0-1+pmx8
libjs-extjs: 7.0.0-4
libknet1: 1.28-pve1
libproxmox-acme-perl: 1.5.0
libproxmox-backup-qemu0: 1.4.1
libproxmox-rs-perl: 0.3.3
libpve-access-control: 8.1.2
libpve-apiclient-perl: 3.3.1
libpve-common-perl: 8.1.1
libpve-guest-common-perl: 5.0.6
libpve-http-server-perl: 5.0.5
libpve-network-perl: 0.9.5
libpve-rs-perl: 0.8.8
libpve-storage-perl: 8.1.0
libspice-server1: 0.15.1-1
lvm2: 2.03.16-2
lxc-pve: 5.0.2-4
lxcfs: 5.0.3-pve4
novnc-pve: 1.4.0-3
proxmox-backup-client: 3.1.4-1
proxmox-backup-file-restore: 3.1.4-1
proxmox-kernel-helper: 8.1.0
proxmox-mail-forward: 0.2.3
proxmox-mini-journalreader: 1.4.0
proxmox-offline-mirror-helper: 0.6.5
proxmox-widget-toolkit: 4.1.4
pve-cluster: 8.0.5
pve-container: 5.0.8
pve-docs: 8.1.4
pve-edk2-firmware: not correctly installed
pve-firewall: 5.0.3
pve-firmware: 3.9-2
pve-ha-manager: 4.0.3
pve-i18n: 3.2.1
pve-qemu-kvm: 8.1.5-3
pve-xtermjs: 5.3.0-3
qemu-server: 8.0.10
smartmontools: 7.3-pve1
spiceterm: 3.3.0
swtpm: 0.8.0+pve1
vncterm: 1.8.0
zfsutils-linux: 2.2.2-pve2

 

[emunt6]

Hi!

Its some kind of bug

Can you try this?

 cpu: host
switch to
 cpu: kvm64

 

[Yazik]

Hi!

Its some kind of bug

Can you try this?

 cpu: host
switch to
 cpu: kvm64

Yes, sure!

It's not help. 1400 MHz on both guests...

I run sysbench on 1 thread and have almost same result. I think performance is good, right?
On screen left side pve-host

 

[LnxBil]

The cpu frequency is not updated regularly on the guest, yet it is still switching on the PVE side.

 

[Nuke Bloodaxe]

Just out of interest, try putting the guests under load, and then measure their Mhz at that point; perhaps they will adjust according to load.
I sometimes find it can also help to assume that the machine might not be doing what you tell it, see what happens with and without the various power state flags.

Note: I have seen people with odd problems before with some of these Intel CPUs.

 

[Yazik]

The cpu frequency is not updated regularly on the guest, yet it is still switching on the PVE side.

But strange, why i see only 1400MHz in guest, not 2200?

So, i run geekbench on pve-host and on VM. They have same result, so i think it's ok with my performance.
https://browser.geekbench.com/v6/cpu/5325388
https://browser.geekbench.com/v6/cpu/5325554

 

[emunt6]

Yes, sure!

It's not help. 1400 MHz on both guests...

I run sysbench on 1 thread and have almost same result. I think performance is good, right?
On screen left side pve-host

SMP enabled in BIOS ?
("Hyperthreading" on Intel CPU)

Can you check with the following settings?
> SMP disabled in BIOS
> VM config "cpu: host"

I think this is kind of bug when SMP is enbaled.
(I always disable SMP and PowerSaving options in BIOS).