How to find the number of CPU cores including virtual?

How do I find out the number of cores my CPU has, including virtual cores (hyper threading cores) using the command line?

6 Answers

You can count no of CPUs

cat /proc/cpuinfo | grep processor | wc -l 

Output :

2 

To check the number of cores !

cat /proc/cpuinfo | grep 'core id' core id : 0 core id : 1 

Or

 $ nproc 2 

Or lscpu will show you all output:

lscpu Architecture: i686 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 2 On-line CPU(s) list: 0,1 Thread(s) per core: 1 Core(s) per socket: 2 Socket(s): 1 Vendor ID: GenuineIntel CPU family: 15 Model: 4 Stepping: 7 CPU MHz: 2792.992 BogoMIPS: 5585.98 L1d cache: 16K L2 cache: 1024K 

To add to the existing answers, you can determine information about Intel's HyperThreading by looking at the "siblings" line in /proc/cpuinfo. The example below is from a 2 socket machine. It shows the CPU has 6 cores but 12 "siblings". On Intel CPUs this means HyperThreading is enabled and there are 6 physical cores.

processor : 23 vendor_id : GenuineIntel cpu family : 6 model : 62 model name : Intel(R) Xeon(R) CPU E5-2430 v2 @ 2.50GHz stepping : 4 microcode : 0x428 cpu MHz : 1599.707 cache size : 15360 KB physical id : 1 siblings : 12 core id : 5 cpu cores : 6 apicid : 43 initial apicid : 43 fpu : yes fpu_exception : yes cpuid level : 13 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm ida arat xsaveopt pln pts dtherm tpr_shadow vnmi flexpriority ept vpid fsgsbase smep erms bogomips : 5005.20 clflush size : 64 cache_alignment : 64 address sizes : 46 bits physical, 48 bits virtual power management: 

dmidecode is also useful for determining what hardware a Linux system is running on.

/proc/cpuinfo contains all the CPUs for my computer, including virtual. You can count them with a little grep:

grep -Pc '^processor\t' /proc/cpuinfo 

Assuming you don't turn off your cores/threads, this command will answer your question:

getconf _NPROCESSORS_ONLN 

You can also install htop (a fancier version of top) which will show you all your cores.

sudo apt-get install htop

Then start it: htop

Type:

 lscpu |grep 'CPU(s)' 

You will get among other few lines, this one:

CPU(s) 4 

You can get 1, 2 ... in place of 4, depending on your CPU, and that is the number of cores your CPU has.