The systems I am working with have 80 or more cores in them. I’ve recently had to investigate processes around core start up. Here are my notes.

The sys file system is used to expose Linux constructs to user space. One place we can see ACPI based information is in /sys/firmware/acpi

I have an Ampere Altra-Max/INGRASYS Yushan Server System running Centos 8 stream.

Because we are a chip manufacteror, we don’t sell end systems, we provide a reference platform that is a starting point for our customers to make a product. This leads to bizarre set of internal versus external names. One thing that you can rely on, however, is the identifier of the processor itself:

# cat /proc/cpuinfo 
processor	: 0
BogoMIPS	: 50.00
Features	: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp ssbs
CPU implementer	: 0x41
CPU architecture: 8
CPU variant	: 0x3
CPU part	: 0xd0c
CPU revision	: 1
...

TO make this readable, use the utility lscpu:

[root@eng14sys-r
111 ~]# lscpu 
Architecture:        aarch64
Byte Order:          Little Endian
CPU(s):              80
On-line CPU(s) list: 0-79
Thread(s) per core:  1
Core(s) per socket:  80
Socket(s):           1
NUMA node(s):        1
Vendor ID:           ARM
BIOS Vendor ID:      Ampere(R)
Model:               1
Model name:          Neoverse-N1
BIOS Model name:     Ampere(R) Altra(R) Processor
Stepping:            r3p1
CPU max MHz:         3000.0000
CPU min MHz:         1000.0000
BogoMIPS:            50.00
L1d cache:           64K
L1i cache:           64K
L2 cache:            1024K
NUMA node0 CPU(s):   0-79
Flags:               fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp ssbs

I want to build the latest Linus-repo Linux Kernel and run it on the server. Here’s the steps I went through.