use cpu_features to detect Granite Rapids and newer

[bedroge]

This is a first attempt to use Google's cpu_features tool to detect the CPU flags of Intel Sapphire Rapids CPUs or newer generations. This tool detects more flags than the ones reported in /proc/cpuinfo, and we can use it to properly distinguish e.g. Granite Rapids from Sapphire Rapids.

WIP, still needs:

• cpu_features to be available somehow (compat layer?)
• tests
• some cleaning up

But the idea seems to work, tested on a Granite Rapids node (with an EB-installed cpu_features):

$ ./eessi_archdetect.sh -d cpupath
2026-09-18 14:41:57 [DEBUG] cpupath: Override variable set as '' 
2026-09-18 14:41:57 [DEBUG] cpupath: Host CPU architecture identified as 'x86_64'
2026-09-18 14:41:57 [DEBUG] cpupath: CPU vendor of host system: 'GenuineIntel'
2026-09-18 14:41:57 [DEBUG] cpupath: Known CPU vendors: GenuineIntel GenuineIntel GenuineIntel GenuineIntel GenuineIntel GenuineIntel AuthenticAMD AuthenticAMD AuthenticAMD AuthenticAMD
2026-09-18 14:41:57 [DEBUG] cpupath: CPU flags of host system: 'fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq monitor ssse3 fma cx16 pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch cpuid_fault ssbd ibrs ibpb stibp ibrs_enhanced fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid avx512f avx512dq rdseed adx smap avx512ifma clflushopt clwb avx512cd sha_ni avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves avx_vnni avx512_bf16 wbnoinvd ida arat avx512vbmi umip pku ospke waitpkg avx512_vbmi2 gfni vaes vpclmulqdq avx512_vnni avx512_bitalg tme avx512_vpopcntdq rdpid bus_lock_detect cldemote movdiri movdir64b md_clear serialize amx_bf16 avx512_fp16 amx_tile amx_int8 flush_l1d arch_capabilities'
2026-09-18 14:41:57 [DEBUG] cpupath: host CPU best match updated to x86_64/intel/haswell
2026-09-18 14:41:57 [DEBUG] cpupath: host CPU best match updated to x86_64/intel/skylake_avx512
2026-09-18 14:41:57 [DEBUG] cpupath: host CPU best match updated to x86_64/intel/cascadelake
2026-09-18 14:41:57 [DEBUG] cpupath: host CPU best match updated to x86_64/intel/icelake
2026-09-18 14:41:57 [DEBUG] cpupath: host CPU best match updated to x86_64/intel/sapphirerapids
2026-09-18 14:41:57 [DEBUG] cpupath: refining Sapphire Rapids match (family='6', model='173')
2026-09-18 14:41:57 [DEBUG] Calling list_cpu_features tool to find all relevant CPU flags
2026-09-18 14:41:57 [DEBUG] Flags reported by list_cpu_features: adx aes amx_bf16 amx_fp16 amx_int8 amx_tile avx avx2 avx512_bf16 avx512_fp16 avx512_second_fma avx512bitalg avx512bw avx512cd avx512dq avx512f avx512ifma avx512vbmi avx512vbmi2 avx512vl avx512vnni avx512vpopcntdq avx_vnni bmi1 bmi2 clflushopt clfsh clwb cx16 cx8 erms f16c fma fpu fs_rep_cmpsb_scasb fs_rep_stosb fz_rep_movsb gfni lzcnt mmx movbe movdir64b movdiri pclmulqdq popcnt rdrnd rdseed sha ss sse sse2 sse3 sse4_1 sse4_2 ssse3 tsc vaes vpclmulqdq
2026-09-18 14:41:57 [DEBUG] cpupath: host CPU best match updated to x86_64/intel/haswell
2026-09-18 14:41:57 [DEBUG] cpupath: host CPU best match updated to x86_64/intel/skylake_avx512
2026-09-18 14:41:57 [DEBUG] cpupath: host CPU best match updated to x86_64/intel/sapphirerapids
2026-09-18 14:41:57 [DEBUG] cpupath: host CPU best match updated to x86_64/intel/graniterapids
2026-09-18 14:41:57 [INFO] cpupath: best match for host CPU: x86_64/intel/graniterapids
x86_64/intel/graniterapids

[bedroge]

As a reference, this is what list_cpu_features reports on a GR node:

$ list_cpu_features 
arch            : x86
brand           : Intel(R) Xeon(R) 6975P-C
family          :   6 (0x06)
model           : 173 (0xAD)
stepping        :   1 (0x01)
uarch           : X86_UNKNOWN
flags           : adx,aes,amx_bf16,amx_fp16,amx_int8,amx_tile,avx,avx2,avx512_bf16,avx512_fp16,avx512_second_fma,avx512bitalg,avx512bw,avx512cd,avx512dq,avx512f,avx512ifma,avx512vbmi,avx512vbmi2,avx512vl,avx512vnni,avx512vpopcntdq,avx_vnni,bmi1,bmi2,clflushopt,clfsh,clwb,cx16,cx8,erms,f16c,fma3,fpu,fs_rep_cmpsb_scasb,fs_rep_stosb,fz_rep_movsb,gfni,lzcnt,mmx,movbe,movdir64b,movdiri,pclmulqdq,popcnt,rdrnd,rdseed,sha,ss,sse,sse2,sse3,sse4_1,sse4_2,ssse3,tsc,vaes,vpclmulqdq
cache_info      : {"level":1,"cache_type":"data","cache_size":49152,"ways":12,"line_size":64,"tlb_entries":64,"partitioning":1},{"level":1,"cache_type":"instruction","cache_size":65536,"ways":16,"line_size":64,"tlb_entries":64,"partitioning":1},{"level":2,"cache_type":"unified","cache_size":2097152,"ways":16,"line_size":64,"tlb_entries":2048,"partitioning":1},{"level":3,"cache_type":"unified","cache_size":503316480,"ways":16,"line_size":64,"tlb_entries":491520,"partitioning":1}

While /proc/cpuinfo has:

processor	: 0
vendor_id	: GenuineIntel
cpu family	: 6
model		: 173
model name	: Intel(R) Xeon(R) 6975P-C
stepping	: 1
microcode	: 0x1000434
cpu MHz		: 2700.000
cache size	: 491520 KB
physical id	: 0
siblings	: 16
core id		: 0
cpu cores	: 8
apicid		: 0
initial apicid	: 0
fpu		: yes
fpu_exception	: yes
cpuid level	: 36
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq monitor ssse3 fma cx16 pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch cpuid_fault ssbd ibrs ibpb stibp ibrs_enhanced fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid avx512f avx512dq rdseed adx smap avx512ifma clflushopt clwb avx512cd sha_ni avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves avx_vnni avx512_bf16 wbnoinvd ida arat avx512vbmi umip pku ospke waitpkg avx512_vbmi2 gfni vaes vpclmulqdq avx512_vnni avx512_bitalg tme avx512_vpopcntdq rdpid bus_lock_detect cldemote movdiri movdir64b md_clear serialize amx_bf16 avx512_fp16 amx_tile amx_int8 flush_l1d arch_capabilities
bugs		: spectre_v1 spectre_v2 spec_store_bypass swapgs bhi spectre_v2_user
bogomips	: 5400.00
clflush size	: 64
cache_alignment	: 64
address sizes	: 48 bits physical, 48 bits virtual
power management:

And lscpu:

$ lscpu 
Architecture:                aarch64
  CPU op-mode(s):            32-bit, 64-bit
  Byte Order:                Little Endian
CPU(s):                      2
  On-line CPU(s) list:       0,1
Vendor ID:                   ARM
  Model name:                Neoverse-N1
    Model:                   1
    Thread(s) per core:      1
    Core(s) per socket:      2
    Socket(s):               1
    Stepping:                r3p1
    BogoMIPS:                243.75
    Flags:                   fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp
Caches (sum of all):         
  L1d:                       128 KiB (2 instances)
  L1i:                       128 KiB (2 instances)
  L2:                        2 MiB (2 instances)
  L3:                        32 MiB (1 instance)
NUMA:                        
  NUMA node(s):              1
  NUMA node0 CPU(s):         0,1
Vulnerabilities:             
  Gather data sampling:      Not affected
  Indirect target selection: Not affected
  Itlb multihit:             Not affected
  L1tf:                      Not affected
  Mds:                       Not affected
  Meltdown:                  Not affected
  Mmio stale data:           Not affected
  Reg file data sampling:    Not affected
  Retbleed:                  Not affected
  Spec rstack overflow:      Not affected
  Spec store bypass:         Mitigation; Speculative Store Bypass disabled via prctl
  Spectre v1:                Mitigation; __user pointer sanitization
  Spectre v2:                Mitigation; CSV2, BHB
  Srbds:                     Not affected
  Tsa:                       Not affected
  Tsx async abort:           Not affected
  Vmscape:                   Not affected
[bedroge@login1 ~]$ srun -p x86-64-intel-grapids-node -c 16 --mem=0 --time=3-00:00:00 --pty /bin/bash
[bedroge@x86-64-intel-grapids-node1 ~]$ lscpu 
Architecture:                x86_64
  CPU op-mode(s):            32-bit, 64-bit
  Address sizes:             48 bits physical, 48 bits virtual
  Byte Order:                Little Endian
CPU(s):                      16
  On-line CPU(s) list:       0-15
Vendor ID:                   GenuineIntel
  Model name:                Intel(R) Xeon(R) 6975P-C
    CPU family:              6
    Model:                   173
    Thread(s) per core:      2
    Core(s) per socket:      8
    Socket(s):               1
    Stepping:                1
    BogoMIPS:                5400.00
    Flags:                   fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc arch_perf
                             mon rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq monitor ssse3 fma cx16 pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt ts
                             c_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch cpuid_fault ssbd ibrs ibpb stibp ibrs_enhanced fsgsbase tsc_adjust bmi1 avx
                             2 smep bmi2 erms invpcid avx512f avx512dq rdseed adx smap avx512ifma clflushopt clwb avx512cd sha_ni avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves avx_v
                             nni avx512_bf16 wbnoinvd ida arat avx512vbmi umip pku ospke waitpkg avx512_vbmi2 gfni vaes vpclmulqdq avx512_vnni avx512_bitalg tme avx512_vpopcntdq rdpid 
                             bus_lock_detect cldemote movdiri movdir64b md_clear serialize amx_bf16 avx512_fp16 amx_tile amx_int8 flush_l1d arch_capabilities
Virtualization features:     
  Hypervisor vendor:         KVM
  Virtualization type:       full
Caches (sum of all):         
  L1d:                       384 KiB (8 instances)
  L1i:                       512 KiB (8 instances)
  L2:                        16 MiB (8 instances)
  L3:                        480 MiB (1 instance)
NUMA:                        
  NUMA node(s):              1
  NUMA node0 CPU(s):         0-15
Vulnerabilities:             
  Gather data sampling:      Not affected
  Indirect target selection: Not affected
  Itlb multihit:             Not affected
  L1tf:                      Not affected
  Mds:                       Not affected
  Meltdown:                  Not affected
  Mmio stale data:           Not affected
  Reg file data sampling:    Not affected
  Retbleed:                  Not affected
  Spec rstack overflow:      Not affected
  Spec store bypass:         Mitigation; Speculative Store Bypass disabled via prctl
  Spectre v1:                Mitigation; usercopy/swapgs barriers and __user pointer sanitization
  Spectre v2:                Mitigation; Enhanced / Automatic IBRS; IBPB conditional; PBRSB-eIBRS Not affected; BHI BHI_DIS_S
  Srbds:                     Not affected
  Tsa:                       Not affected
  Tsx async abort:           Not affected
  Vmscape:                   Not affected