Server and Proxmox show 255 cores

[starnetwork]

Hi,
I have some Proxmox 7.4.x ENV with 2x AMD 7763 CPUs and I see 256 Cores, and on another new Proxmox 8.1 I see only 255 Cores for same AMD CPU model 7763

Suggestions? any setting that related to missing core?

Thanks!

 

[alexskysilk]

how interesting!

what does /proc/cpuinfo show for count?

 

[starnetwork]

how interesting!

what does /proc/cpuinfo show for count?

it's show 256 cores, count from 0 to 255
btw, Something else interesting, if I disable the logical cores option on bios and count only "physical" cores, it's show 128 and not 127
it's should consider some proxmox gui should fix and count 1-256 instead of 0-255?

 

[bbgeek17]

Counting CPU cores from 0 is somewhat historical, but is also dependent on CPU architecture, vendor BIOS/firmware and OS Kernel. Dell is known to occasionally program proprietary CPU offsets in their firmware, for example.

Between PVE 7 and 8 you have a major kernel change from 5.x to 6.x. I believe PVE reports the number contained in SYSFS, and would be unlikely to create special reporting for select architectures.

---

Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox

 

[bindi]

grep CONFIG_NR_CPUS /boot/config-$(uname -r)

What does this say on both of the hosts? I remember that Ubuntu's kernel used to be limited to 255 cores. Or maybe it was 256..

Anyway, are all of the CPUs online? This should print the CPUs which are offline:

grep -L 1 /sys/devices/system/cpu/cpu*/online | awk -F/ '{print $6}'