Re: nr_cpu_ids vs AMD 3970x(32 physical CPUs)

From: Uladzislau Rezki
Date: Fri Jul 03 2020 - 15:28:13 EST


> > Hello, folk.
> >
> > I have a system based on AMD 3970x CPUs. It has 32 physical cores
> > and 64 threads. It seems that "nr_cpu_ids" variable is not correctly
> > set on latest 5.8-rc3 kernel. Please have a look below on dmesg output:
> >
> > <snip>
> > urezki@pc638:~$ sudo dmesg | grep 128
> > [ 0.000000] IOAPIC[0]: apic_id 128, version 33, address 0xfec00000, GSI 0-23
> > [ 0.000000] smpboot: Allowing 128 CPUs, 64 hotplug CPUs
> > [ 0.000000] setup_percpu: NR_CPUS:512 nr_cpumask_bits:512 nr_cpu_ids:128 nr_node_ids:1
>
> My 3950 do
>
>
> [ÂÂÂ 0.005271] ACPI: SSDT 0x00000000CA1F5000 0003F1 (v02 ALASKA CPUSSDTÂ 01072009 AMIÂ 01072009)
> [ÂÂÂ 0.108266] smpboot: Allowing 32 CPUs, 0 hotplug CPUs
> [ÂÂÂ 0.111384] setup_percpu: NR_CPUS:8192 nr_cpumask_bits:32 nr_cpu_ids:32 nr_node_ids:1
>
> (Fedora F32Â 5.6.18-300) What motherboard and BIOs do you use?
>
I have MSI TRX40 with latest BIOS.

--
Vlad Rezki