How to determine the number of physical CPUs on Linux

Tue, 17 Jul 2012 15:51:00 +0100

The /proc/cpuinfo file contains information about the CPUs installed on your computer however it’s quite confusing when you have to deal with multi-core processors.

- list number of physical CPUs:

$ cat /proc/cpuinfo | grep "physical id" | sort | uniq | wc -l
1

- number of cores:

$ cat /proc/cpuinfo | grep "cpu cores" | uniq
cpu cores : 2

- how many virtual processors:

$ cat /proc/cpuinfo | grep "^processor"
processor : 0
processor : 1

If the number of virtual processors is greater than the number of physical processors, the CPUs are using hyper-threading. Hyper-threading will only work with the SMP kernel.

/Proc/Cpuinfo on myshell.co.uk

How to determine the number of physical CPUs on Linux

- list number of physical CPUs:

- number of cores:

- how many virtual processors: