Linux: cpu information processor vs core vs socket

When you run /proc/cpuinfo on linux system, you get the cpu information of the hardware.

I try to explain how to interpret the cpu infomation in order to understand the number of physical processors and whether it is single or dual or quad core and whether hyperthreading is enabled.


processor:    Defines the number of processors on the system (logical)
physical id:   Number of CPU Sockets (physical) - Also referred as Chip - This is what is plugged onto mother board.
core id:        Identifies a particular logical core
cpu cores:    Number of cores (1-Single/2-Dual/4-Quad/8-Octa)
siblings:        Indicates whether hyper threading enabled. If "Number of cores" == siblings, then hyper threading is OFF ; else ON

For e.g look at the below sample:


[root@myhome ~]# cat /proc/cpuinfo | /bin/egrep 'processor|physical |core|sibl' | tr -d "\n" | sed s/processor/\\nprocessor/g | grep -v ^$ | sort -u
processor       : 0physical id  : 1siblings     : 8core id              : 0cpu cores    : 4
processor       : 1physical id  : 1siblings     : 8core id              : 2cpu cores    : 4
processor       : 2physical id  : 1siblings     : 8core id              : 1cpu cores    : 4
processor       : 3physical id  : 1siblings     : 8core id              : 3cpu cores    : 4
processor       : 4physical id  : 1siblings     : 8core id              : 0cpu cores    : 4
processor       : 5physical id  : 1siblings     : 8core id              : 2cpu cores    : 4
processor       : 6physical id  : 1siblings     : 8core id              : 1cpu cores    : 4
processor       : 7physical id  : 1siblings     : 8core id              : 3cpu cores    : 4

Physical id  => 1 => Single CPU Socket/Chip

Cpu cores   => 4 => Quad Core Processor

This system has 1 Physical CPU Socket - Quad Core Processor configured with hyper threading ON...