Brontekst bekijken van Processors, cores & threads on this computer (Bash)

How many ''processors'', ''cores'' or ''threads'' does a given computer have? And which of these entities do I actually need?

== Use case ==

I want to parallelise Bash commands and I want to know how many parallel threads I can have. I have the impression that I am actually looking for ''processors'' or ''processing units''.

== The answers... ==

* First of all: It's indeed ''processing units'' that I'm looking for. Not something like threads or whatever
* Secondly: All tools below give the same answers.

{| class="wikitable" border="1"
|-
! Computer
! External documentation
! nproc
! lscpu
! /proc/cpuinfo
|-
|bal1
| --
| 6
| 
* CPUs: 6
* Threads/core: 1
* Cores/socket: 6
* Sockets: 1
| 6
|-
|bal5 
| TransIP: 2 cores
| 2
|
* Sockets: 1
* Cores/socket: 2
* Thread/core: 1
* CPUs: 2
| 2
|-
|dell2020
| --
| 8
|
* CPUs: 8
* Threads/core: 2
* Cores/socket: 4
* Sockets: 1
| 8
|-
| dvb8
| TransIP: 8 cores
| 8
|
* CPUs: 8
* threads/core: 2
* Cores/socket: 4
* Sockets: 1
| 8
|}

== getconf ==

* Use <code>getconf -a</code> to get all information - Some screens full
* Use <code>getconf -v specification</code> for a specific aspect. E.g.: <code>getconf -v NZERO</code>.

What seems to get closed to what I'm looking for (output <code>getconf -a</code>) For my laptop (Dell2020 - Nov. 2022):

<pre>
_NPROCESSORS_CONF                  8
_NPROCESSORS_ONLN                  8
</pre>

But I can't get this to work with

<pre>
getconf -v _NPROCESSORS_CONF
getconf -v _NPROCESSORS_ONLN
</pre>

Maybe find a better way.

== nproc ==

<code>nproc</code> geeft het aantal processors weer, niet het aantal threads:Processors, cores & threads on this computer (Bash)

<pre>
$ nproc
8
</pre>

== lscpu ==

<pre>
$ lscpu

Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                6
On-line CPU(s) list:   0-5
Thread(s) per core:    1
Core(s) per socket:    1
Socket(s):             6
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 85
Model name:            Intel(R) Xeon(R) Gold 6140 CPU @ 2.30GHz
Stepping:              4
CPU MHz:               2494.096
BogoMIPS:              4988.19
Virtualization:        VT-x
Hypervisor vendor:     KVM
Virtualization type:   full
L1d cache:             32K
L1i cache:             32K
L2 cache:              4096K
NUMA node0 CPU(s):     0-5
Flags:                 fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon rep_good nopl pni pclmulqdq vmx ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch invpcid_single ssbd ibrs ibpb kaiser tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid mpx avx512f avx512dq rdseed adx smap clflushopt clwb avx512cd avx512bw avx512vl xsaveopt xsavec xgetbv1 pku ospke md_clear
</pre>

In dit geval 6.

== /proc/cpuinfo ==

Dit komt in de buurt:

<pre>
echo "#CPUs: $(grep -c processor /proc/cpuinfo)"
</pre>

Dit ook:

<pre>
grep processor /proc/cpuinfo | wc -l
</pre>

== Bronnen ==

* https://www.cyberciti.biz/faq/check-how-many-cpus-are-there-in-linux-system/
* https://unix.stackexchange.com/questions/218074/how-to-know-number-of-cores-of-a-system-in-linux