Ryzen 4000 CPU Performance Issues (Lockups)

[dylangerdaly]

Qubes OS version
4.1

Affected component(s) or functionality
Entire OS/Experience

Brief summary
There appears to be something wrong with the CPU, every 3-5 seconds everything will lockup, here's a GIF for visuals.

I've confirmed this is specific to AMD 4000 CPUs because 4.1 running on a i7-1065G7 works fine (Still at a much slower rate than 4.0.3 but that's beside the point)

To Reproduce

Steps to reproduce the behavior:

1. Install Qubes 4.1 onto a Lenovo X13 or any AMD Ryzen 4000 Laptop
2. Observe weird lockups and full hangs

Expected behavior
Smooth as butter 8 Core experience

Actual behavior
Terrible lockups every 3-5 seconds with full hangs peppered in randomly

Screenshots
See GIF in Brief

Additional context
NIL

Solutions you've tried
Not sure how/where to troubleshoot this, I assume it has something to do with Xen.

[0spinboson]

kernel-latest installed?

[dylangerdaly]

Indeed, 5.8.8-200, 4.14-3 Xen

[0spinboson]

ah, yes. try going back to Xen 4.13.1-4 in dom0. 4.14 was terrible for me too, wrt graphics performance that is.

[dylangerdaly]

Aw, I can't, Ryzen 4000 series CPUs won't boot unless I'm using 4.14, I think I'll just need to wait for 4.15?

Can I rebase 4.14 to Xen's Master? I don't think Marek has made many changes to Xen

[0spinboson]

I dunno, it probably needs troubleshooting to get it working right on 4.14, I just didn't really know where to look for error reports. (To be clear, I didn't have CPU lockups, just display issues once I opened more than a few VM windows concurrently.)

[dylangerdaly]

Oooooooo thank for @0spinboson for point me in the right direction

I think this has been fixed via adding processor.max_cstate=5 to CMDLINE, I'm no longer getting softlocks and it's 🧈 smooth.

I'll do some more testing before I close this issue 🎉

[dylangerdaly]

Hm, not quite, it worked for one boot, but not subsequent boots.

It does seem to be related to a public AMD issue because the bug is everywhere.

Fedora Workstation 32 Live USB works just fine, I'll have a look at it's default CMDLINE.