How can I monitor the thread count of a process on linux?

Question

I would like to monitor the number of threads used by a specific process on Linux. Is there an easy way to get this information without impacting the performance of the proc

Answer 1

Here is one command that displays the number of threads of a given process :

ps -L -o pid= -p <pid> | wc -l

Unlike the other ps based answers, there is here no need to substract 1 from its output as there is no ps header line thanks to the -o pid=option.

Answer 2

ps -eLf on the shell shall give you a list of all the threads and processes currently running on the system. Or, you can run top command then hit 'H' to toggle thread listings.

Answer 3

If you are trying to find out the number of threads using cpu for a given pid I would use:

top -bc -H -n2 -p <pid> | awk '{if ($9 != "0.0" && $1 ~ /^[0-9]+$/) print $1 }' | sort -u | wc -l

Answer 4

try

ps huH p <PID_OF_U_PROCESS> | wc -l

or htop

Answer 5

The easiest way is using "htop". You can install "htop" (a fancier version of top) which will show you all your cores, process and memory usage.

Press "Shift+H" to show all process or press again to hide it. Press "F4" key to search your process name.

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.

Answer 6

JStack is quite inexpensive - one option would be to pipe the output through grep to find active threads and then pipe through wc -l.

More graphically is JConsole, which displays the thread count for a given process.