An Opteron 6128 shows up as follows in /proc/cpuinfo
:
$ cat /proc/cpuinfo | grep -e ^core -e ^phys
physical id : 0
core id : 0
physical id : 0
core id : 1
physical id : 0
core id : 2
physical id : 0
core id : 3
physical id : 0
core id : 0
physical id : 0
core id : 1
physical id : 0
core id : 2
physical id : 0
core id : 3
... (other physical id's)
My understanding so far has been that different cores within the same physical CPU would have different core id
, and if core id
s are identical, this is due to hyperthreading. So one should interpret this /proc/cpuinfo
entry as a 4-core CPU with hyperthreading.
However, Opteron 6128 is really 8-core. What's going on here?
P.S. Full entry for the 8th "processor":
processor : 7
vendor_id : AuthenticAMD
cpu family : 16
model : 9
model name : AMD Opteron(tm) Processor 6128
stepping : 1
cpu MHz : 800.000
cache size : 512 KB
physical id : 0
siblings : 8
core id : 3
cpu cores : 8
apicid : 23
initial apicid : 7
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc rep_good nonstop_tsc extd_apicid amd_dcm pni monitor cx16 popcnt lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt nodeid_msr npt lbrv svm_lock nrip_save pausefilter
bogomips : 3999.89
TLB size : 1024 4K pages
clflush size : 64
cache_alignment : 64
address sizes : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc 100mhzsteps hwpstate