CPU MHZ and Cache Different in VM than host.

[Unknown2k]

All,
I have a Intel i7-4790K. In the shell of the debian/proxmox cat /proc/cpuinfo shows it as being 4.4ghz and a cache size 8192

However, when I create a VM, and do cat /proc/cpuinfo from within the VM it is reporting mhz 3.9 and a cache of only 4096

Is there anyway to utilize the CPU's full cache and clock speed in the VM?

 

[Unknown2k]

If I create a CT instead of a VM, I get full use of the CPU Clock and Cache. I'd rather use VM though.

 

[sigxcpu]

I don't think it matters what it is shown there.

 

[wosp]

What CPU type did you assign to the VM? I don't know, but may be a limitation of the default CPU (kvm64), I think you are using.

Can you try to change CPU type to "host" in Proxmox and check again?

Please not that keeping CPU type to "host" is only a good idea if you have only the same physical CPU's in your nodes or your running standalone (https://pve.proxmox.com/wiki/Allow_Guests_Access_to_Host_CPU)

 

[Unknown2k]

Hi Wosp,
I appreciate your time answering.

I tried Host, in addition to Haswell. No matter what I tried, I couldn't get the VM to utilize the CPU's full clock or cache. It made a huge difference in an app I was hosting that is single core, so missing the clock speed and cache was painful.

I've setup the app in a CT and it is able to access the entire Clock and cache. I would have preferred to use a VM, but I'll live with a CT for this app.

If anyone knows a solution, I'd still like to hear it for future needs

 

[spirit]

on your host, can you try to add in grub options "intel_pstate=disable"

/etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_pstate=disable "

#update-grub
#reboot


With like, I have always full speed on my cpu. (host and guest).

 

[Unknown2k]

I will try that! Thanks.

 

[Unknown2k]

No Luck. :/

 

[sigxcpu]

Again, it doesn't matter what freq/cache say. The execution speed is the same.