AshKeys

Confessions and Confusions of Ashok M A. Personal and Professional Blog.

Ashok Mannolu Arunachalam, LinuxPop!_OSTerminal
Back

How to list the number of threads ran by a process in linux

Recently I have noticed that one of our applications crossed the allowed threshold for creating new threads in a test server. After a talk with Ops guy, we gotta to know that it had around 5k+ (O_O) threads running already for no reason. Probably a memory leak that we can have it for another day.

For now, let me share you the way to find the process and its threads in linux.

Know the process id.

First of all, we need the process id in order to list out the threads being created by said process.

shell
$ top -H -u ashokma
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3173 ashokma 20 0 2720980 429424 99644 S 5.6 2.7 4:49.63 Compositor
3166 ashokma 20 0 2720980 429424 99644 S 4.6 2.7 1:53.81 teams

Let's take the process teams for instance. It's id is 3166.

List the number of threads

Using the following command we can list out the number of threads.

shell
$ ps -T -p 3166
PID SPID TTY TIME CMD
3166 3166 ? 00:02:02 teams
3166 3168 ? 00:00:00 ThreadPoolServi
3166 3170 ? 00:01:47 Chrome_ChildIOT
3166 3171 ? 00:00:00 GpuMemoryThread
3166 3173 ? 00:05:17 Compositor
3166 3174 ? 00:00:00 ThreadPoolSingl
3166 3175 ? 00:00:01 CompositorTileW
3166 3176 ? 00:00:01 CompositorTileW
3166 3177 ? 00:00:01 CompositorTileW
3166 3178 ? 00:00:01 CompositorTileW
3166 3179 ? 00:00:00 CompositorTileW
3166 3180 ? 00:00:00 teams
3166 3184 ? 00:00:00 Watchdog
3166 3199 ? 00:00:01 SharedWorker th
3166 3205 ? 00:00:00 DedicatedWorker
3166 3328 ? 00:00:00 Media
3166 71782 ? 00:00:00 ThreadPoolForeg
3166 71915 ? 00:00:00 ThreadPoolForeg
3166 71916 ? 00:00:00 ThreadPoolForeg
3166 71917 ? 00:00:00 ThreadPoolForeg
3166 71918 ? 00:00:00 ThreadPoolForeg
3166 71919 ? 00:00:00 ThreadPoolForeg
3166 71920 ? 00:00:00 ThreadPoolForeg

Pro Tip: To quickly know the number of threads just chain the above command with wordcount (wc) as follows:

shell
$ ps -T -p 3166 | wc -l
21
# This varies realtime as the threads are being closed and created over the time.