Zen2 cpu governor - Ubuntu 20.04

I am trying to update our compute server (HPE, 2xEpyc 7702) to ubuntu 20.04.
There are some instability issues that seem to stem from either LOM or nVME, but i’ll probably sort that out.

One of the main reasons to upgrade was to be able to set “static” frequency & cpu governor… If i read correctly, this is already possible on zen2 with 5.4 kernel?

However if i try using cpupower of cpufreq-info there’s no option. Is there anything obvious i’m missing? Or is still 5.4 not really good enough for zen2?

Thanks for the info

Fastest way to check is to just switch to 5.9?

So another stupid question:
Is there an official way of doing this under ubuntu?

When i was using desktop version of ubuntu there was ukuu, but that has sometimes caused issues with certain drivers at that time…
Now i see mainline (https://github.com/bkw777/mainline) has been forked. Is this the best way to make sure everything get patched correctly?


Don’t worry about fighting Ubuntu for now.

Instead messing with your system, faster way is to just get iso of the distro which already has 5.9 as default (I believe Manjaro does but not sure).

Boot from that live iso and test what you need to test. If you find out that indeed that was your problem, then you can mess with Ubuntu.

Edit: Oh, and since you have Epyc, and its on server board, then you don’t even have to make bootable usb. Just mount iso trough your ipmi/bmc.

Also make sure you don’t boot with an Nvidia GPU on 5.9 and up. Nvidia is super slow to getting Kernel 5.9 support working.

So it seems that it was probably more issue of old bios (from feb 2020…) :slight_smile:

Under centos 8 everything worked with “ancient” kernel and bios (i guess they backport a lot, and add hpe workarounds).

After updating BIOS, all FW i could (NICs, nvme, iLO…) and another reinstall of Ubuntu, everything works as it should.
Cpupower now works out of the box, and stability seems OK.