Optimal number of threads per core

Princess_40516 0
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Let's say I have a 4-core CPU, and I want to run some process in the minimum amount of time. The process is ideally parallelizable, so I can run chunks of it on an infinite number of threads and each thread takes the same amount of time.

Since I have 4 cores, I don't expect any speedup by running more threads than cores, since a single core is only capable of running a single thread at a given moment. I don't know much about hardware, so this is only a guess.

Is there a benefit to running a parallelizable process on more threads than cores? In other words, will my process finish faster, slower, or in about the same amount of time if I run it using 4000 threads rather than 4 threads?

parallel-processing cpu
13 Answers

You will find how many threads you can run on your machine by running htop or ps command that returns number of process on your machine.

You can use man page about 'ps' command.

man ps

If you want to calculate number of all users process, you can use one of these commands:

  1. ps -aux| wc -l
  2. ps -eLf | wc -l

Calculating number of an user process:

  1. ps --User root | wc -l

Also, you can use "htop" [Reference]:

Installing on Ubuntu or Debian:

sudo apt-get install htop

Installing on Redhat or CentOS:

yum install htop
dnf install htop      [On Fedora 22+ releases]

If you want to compile htop from source code, you will find it here.

user_85841980
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