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#1 2020-11-18 10:14:31

Matombo
Member
Registered: 2020-11-18
Posts: 4

Sysfs buggy with more than 24 virtual cores?

Hi,
I need someone who points me in the right direction:
I have a workstation laptop with a Ryzen 9 3950X, which has 16 physical cores with 2 Threads each, aka 32 virtual cores.
I noticed however that the cpufreq virtual files in sysfs at /sys/devices/system/cpu/cpu*/ are only created for virtual cores cpu0-cpu23. cpu24-cpu31 are missing the cpufreq file (and the driver and firmare_node simlink).
There is also no policy folder for these cores in /sys/devices/system/cpu/cpufreq/.
Am I missing a setting for high cpu count somewhere in the system?

I also tried Ubuntu but it has the same problem.

I also tried different kernel versions: 5.6, 5.8, and 5.10 all with the same problem.

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#2 2020-11-18 13:28:58

Lone_Wolf
Member
From: Netherlands, Europe
Registered: 2005-10-04
Posts: 8,593

Re: Sysfs buggy with more than 24 virtual cores?

what is the output of

$ journalctl -b -g smpboot

for reference here's the output from my threadripper 19020x

$ journalctl -b -g smpboot
-- Logs begin at Wed 2019-09-25 17:40:45 CEST, end at Wed 2020-11-18 14:23:44 CET. --
nov 18 11:04:11 silverbolt kernel: smpboot: Allowing 128 CPUs, 104 hotplug CPUs
nov 18 11:04:11 silverbolt kernel: smpboot: CPU0: AMD Ryzen Threadripper 1920X 12-Core Processor (family: 0x17, model: 0x1, stepping: 0x1)
nov 18 11:04:11 silverbolt kernel: smpboot: Max logical packages: 6
nov 18 11:04:11 silverbolt kernel: smpboot: Total of 24 processors activated (167729.30 BogoMIPS)
$ 

Multi-init booting with apg Openrc and systemd coexisting
Automounting : not needed, i prefer pmount
Aur helpers : makepkg + my own local repo === rarely need them

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#3 2020-11-18 13:48:21

Matombo
Member
Registered: 2020-11-18
Posts: 4

Re: Sysfs buggy with more than 24 virtual cores?

I'm currently still on my ubuntu test install, but the output here is

 -- Logs begin at Wed 2020-11-18 12:49:53 CET, end at Wed 2020-11-18 14:39:24 CET. --
Nov 18 13:03:40 test-TUXEDO-Book-XA1510 kernel: smpboot: Allowing 32 CPUs, 0 hotplug CPUs
Nov 18 13:03:40 test-TUXEDO-Book-XA1510 kernel: smpboot: CPU0: AMD Ryzen 9 3950X 16-Core Processor (family: 0x17, model: 0x71, stepping: 0x0)
Nov 18 13:03:40 test-TUXEDO-Book-XA1510 kernel: smpboot: Max logical packages: 1
Nov 18 13:03:40 test-TUXEDO-Book-XA1510 kernel: smpboot: Total of 32 processors activated (223593.08 BogoMIPS)

I'm creating an arch live usb stick right now to go back to arch and will check if there is any difference.

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#4 2020-11-18 14:04:17

Matombo
Member
Registered: 2020-11-18
Posts: 4

Re: Sysfs buggy with more than 24 virtual cores?

Another thing I tried in the meantime: Compiling cpufreq as a module and unloading and reloading it. Sadly that didn't help.

edit: forgot to write: the journalctl output is the same on the arch live usb

Last edited by Matombo (2020-11-18 14:05:35)

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#5 2020-11-19 12:00:59

Matombo
Member
Registered: 2020-11-18
Posts: 4

Re: Sysfs buggy with more than 24 virtual cores?

Ok trying out the CPU on a different mainboard where it worked just fine, gave the deciding hint: It's a broken ACPI table: https://bugzilla.redhat.com/show_bug.cgi?id=1874538#c2

Last edited by Matombo (2020-11-19 12:07:01)

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