Number of processors cores in command line

Question

I am running the following command to get the number of processors cores in Linux   cat  proc cpuinfo   grep processor   wc -l   It works but it does not look elegant  How would you suggest improve it

User · Answer

If you want to do this so it works on linux and OS X  you can do   CORES   grep -c  processor  proc cpuinfo 2 gt  dev null    sysctl -n hw ncpu

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The lscpu 1  command provided by the util-linux project might also be useful     lscpu Architecture           x86 64 CPU op-mode s          32-bit  64-bit Byte Order             Little Endian CPU s                  4 On-line CPU s  list    0-3 Thread s  per core     2 Core s  per socket     2 Socket s               1 NUMA node s            1 Vendor ID              GenuineIntel CPU family             6 Model                  58 Model name             Intel R  Core TM  i7-3520M CPU   2 90GHz Stepping               9 CPU MHz                3406 253 CPU max MHz            3600 0000 CPU min MHz            1200 0000 BogoMIPS               5787 10 Virtualization         VT-x L1d cache              32K L1i cache              32K L2 cache               256K L3 cache               4096K NUMA node0 CPU s       0-3

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If you need an os independent method  works across Windows and Linux   Use python    python -c  import multiprocessing as m  print m cpu count    16

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This is for those who want to a portable way to count cpu cores on  bsd   nix or solaris  haven t tested on aix and hp-ux but should work   It has always worked for me   dmesg     egrep  cpu      0-9        sed  s      cpu      0-9         1 g      sort -u     wc -l     tr -d       solaris grep  amp  egrep don t have -o option so sed is used instead

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When someone asks for  the number of processors cores  there are 2 answers being requested   The number of  processors  would be the physical number installed in sockets on the machine   The number of  cores  would be physical cores   Hyperthreaded  virtual  cores would not be included  at least to my mind   As someone who writes a lot of programs with thread pools  you really need to know the count of physical cores vs cores hyperthreads   That said  you can modify the following script to get the answers that you need       bin bash  MODEL  cat  cpu procinfo   grep  model name    sort   uniq  ALL  cat  proc cpuinfo   grep  bogo    wc -l  PHYSICAL  cat  proc cpuinfo   grep  physical id    sort   uniq   wc -l  CORES  cat  proc cpuinfo   grep  cpu cores    sort   uniq   cut -d    -f2  PHY CORES     PHYSICAL    CORES   echo  Type  MODEL  echo  Processors  PHYSICAL  echo  Physical cores  PHY CORES  echo  Including hyperthreading cores  ALL    The result on a machine with 2 model Xeon X5650 physical processors each with 6 physical cores that also support hyperthreading   Type model name   Intel R  Xeon R  CPU           X5650    2 67GHz Processors 2 Physical cores 12 Including hyperthreading cores 24   On a machine with 2 mdeol Xeon E5472 processors each with 4 physical cores that doesn t support hyperthreading  Type model name   Intel R  Xeon R  CPU           E5472    3 00GHz Processors 2 Physical cores 8 Including hyperthreading cores 8

User · Answer

nproc is what you are looking for   More here   http   www cyberciti biz faq linux-get-number-of-cpus-core-command

User · Answer

Another one-liner  without counting hyper-threaded cores   lscpu   awk -F       Core    c  2      Socket    print c  2

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On newer kernels you could also possibly use the the  sys devices system cpu  interface to get a bit more information     ls  sys devices system cpu  cpu0  cpufreq  kernel max  offline  possible  present  release cpu1  cpuidle  modalias    online   power     probe    uevent   cat  sys devices system cpu kernel max  255   cat  sys devices system cpu offline  2-63   cat  sys devices system cpu possible  0-63   cat  sys devices system cpu present  0-1   cat  sys devices system cpu online  0-1   See the official docs for more information on what all these mean

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The most simplest tool comes with glibc and is called getconf     getconf  NPROCESSORS ONLN 4

User · Answer

I think the method you give is the most portable on Linux   Instead of spawning unnecessary cat and wc processes  you can shorten it a bit     grep --count  processor  proc cpuinfo 2

[linux] Number of processors/cores in command line

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