linux-processes-threads

Linux Processes vs Threads: When Each One Wins

Video: https://youtu.be/86Wzw9MnxFo
Written version: https://cloudexplainers.com/linux-processes-vs-threads-when-each-one-wins/

Everything below ran for real in the video. Run it in a throwaway machine or container, never on a computer you care about.

Lab files

The machine the video used, as files you can build it from:

• lab/burn.c
• lab/common.h
• lab/counter.c
• lab/crash.c
• lab/spawn.c

Commands, in the order the video runs them

Processes vs threads

# ana@ubuntu:~$
ps -u postgres -o pid,nlwp,args
ps -C mariadbd -o pid,nlwp,comm

What a process is

# ana@ubuntu:~$
ls -l /usr/sbin/nginx
ps -C nginx -o pid,user,nlwp,args

What a thread is

# ana@ubuntu:~$
ps -T -p $(pidof mariadbd) | head -5
ls /proc/$(pidof mariadbd)/task | wc -l

Round 1: Sharing memory

# ana@ubuntu:~$
counter --processes 4
counter --threads 4
counter --threads 4
counter --threads 4 --lock

Round 2: Crashes

# ana@ubuntu:~$
crash --threads 4
crash --processes 4
sudo kill -9 40
ps -C nginx -o pid,user,nlwp,args
curl -sI localhost | head -1

Round 3: Starting one

# ana@ubuntu:~$
spawn --threads 10000
spawn --processes 10000

Round 4: CPU cores

# ana@ubuntu:~$
nproc
burn --threads 4 & sleep 3; ps -C burn -o pid,nlwp,pcpu,comm; wait
burn --processes 4 & sleep 3; ps -C burn -o pid,nlwp,pcpu,comm; wait

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From Cloud Explainers. Lab files are MIT licensed (see the repository's LICENSE).