CPU burst speeds not seen by guest OS

[webtron]

I have a little NUC with an Intel(R) Celeron(R) CPU N3450 @ 1.10GHz which shows cpu MHz : 2089.307 on the host when I run stress on a guest but the guest never shows above the 1094.4.
I'm using PVE 6.2-10 and the guest is Xubuntu 18.04.
Is there some way to make the guests see all the burst speed of the cpu?
Edit: I forgot to mention the guest is qemu

 

[LnxBil]

Is there some way to make the guests see all the burst speed of the cpu?

No, but why do you want it?

Edit: I forgot to mention the guest is qemu

Yes, Containers would see it because the CPU is not virtualized in a container.

 

[webtron]

No, but why do you want it?

For the same reason they have it available to the host, extra power under load.

 

[Uncle Lumpy]

Did you actually measure the burst speeds that the guest is experiencing? In my case, even though the VM is showing the rated speed of the CPU at all times, it is actually running at the burst speed of the CPU. I tested this by running Prime95 (actually mprime) inside both the guest and the host (at different moments, of course) to show that the iteration times for the program were essentially identical between the two. This showed me that the guest VM is running at the full burst speed of the CPU even though it was only reporting running at the lower, rated speed.

Lumpy

 

[LnxBil]

Did you actually measure the burst speeds that the guest is experiencing? In my case, even though the VM is showing the rated speed of the CPU at all times, it is actually running at the burst speed of the CPU. I tested this by running Prime95 (actually mprime) inside both the guest and the host (at different moments, of course) to show that the iteration times for the program were essentially identical between the two. This showed me that the guest VM is running at the full burst speed of the CPU even though it was only reporting running at the lower, rated speed.

Lumpy

Therefore I asked. Just showing the numbers does not offer any benefit, the VM will use the burst clock anyway.

 

[webtron]

In my case, even though the VM is showing the rated speed of the CPU at all times, it is actually running at the burst speed of the CPU.

I've tested the guest and host this morning using stress-ng and they are indeed similar. I couldn't get my head around the results from mprime and stress-ng gave me a quick comparison. Thanks for that.