16.04 - kernel reporting incorrect CPU count - Ask Ubuntu

it ubuntu 16.04

 $ uname -a linux m-x170 4.4.0-42-generic #62-ubuntu smp fri oct 7 23:11:45 utc 2016 x86_64 x86_64 x86_64 gnu/linux 

the processor used xeon e3 1245 v5 spec'ed quad core 8 threads per core.

 dmidecode -t processor shows  core count: 4 core enabled: 4 thread count: 8 characteristics:     64-bit capable     multi-core     hardware thread     execute protection     enhanced virtualization     power/performance control 

 , lscpu shows  $ lscpu architecture:          x86_64 cpu op-mode(s):        32-bit, 64-bit byte order:            little endian cpu(s):                8 on-line cpu(s) list:   0-7 thread(s) per core:    2 core(s) per socket:    4 socket(s):             1 numa node(s):          1 vendor id:             genuineintel cpu family:            6 model:                 94 model name:            intel(r) xeon(r) cpu e3-1245 v5 @ 3.50ghz 

and when queried htt, there too.

 $ sudo dmidecode | grep htt         htt (multi-threading) 

the question is: why lscpu showing 2 threads per core dmidecode reports 8 threads (meaning 8 per core)?

you have 4 cpu cores, hyper threading (htt) support have 1 additional logical core per cpu.

so have:

• 4 physical cores
• 8 logical cores

and results of commands correct.