opposite-bracket / threads-with-nodejs

Learning threading with node.js

threads-with-nodejs

Thiw project is mean to better understand how to do multithreating with nodejs 12.10.0. For this, i installed htop to be able to keep track of the processes and threads.

Before running my node program, i went ahead and (through htop) filter my processes in a tree mode as well as searching for the program i'm running which is node index.js. Right away i can see that nothing is displayed:

Then i went ahead and implemented a simple program which seems to run a single thread with only one worker and this is what it looked like:

As you can see, it spun up a thread with 6 additional workers on top of the one i needed to run. Seeing this, I was currious what would happened if I added 2 more workers.

Interestingly enough, it seems to always add 6 additional workers and this seems to be a patter even when i add 12 workers:

Order of execution completion

Now, i was curious to see how would the workers finish if i wasn't to have a setTimeout so here's the result i've got after a few tries:

Try #1

$ node index.js 
waiting for worker thread0 1 to finish!
false
waiting for worker thread2 3 to finish!
false
waiting for worker thread3 4 to finish!
false
waiting for worker thread4 5 to finish!
false
waiting for worker thread6 7 to finish!
false
waiting for worker thread9 10 to finish!
false
waiting for worker thread11 12 to finish!
false
waiting for worker thread1 2 to finish!
false
waiting for worker thread8 9 to finish!
false
waiting for worker thread5 6 to finish!
false
waiting for worker thread7 8 to finish!
waiting for worker thread10 11 to finish!
false
false

Try #2

$ node index.js 
waiting for worker thread4 5 to finish!
false
waiting for worker thread8 9 to finish!
false
waiting for worker thread3 4 to finish!
waiting for worker thread5 6 to finish!
false
waiting for worker thread0 1 to finish!
false
waiting for worker thread1 2 to finish!
false
waiting for worker thread2 3 to finish!
false
false
waiting for worker thread6 7 to finish!
false
waiting for worker thread10 11 to finish!
waiting for worker thread11 12 to finish!
false
waiting for worker thread7 8 to finish!
false
waiting for worker thread9 10 to finish!
false
false

Try #3

$ node index.js 
waiting for worker thread0 1 to finish!
false
waiting for worker thread1 2 to finish!
false
waiting for worker thread6 7 to finish!
false
waiting for worker thread2 3 to finish!
false
waiting for worker thread9 10 to finish!
waiting for worker thread3 4 to finish!
false
false
waiting for worker thread5 6 to finish!
false
waiting for worker thread7 8 to finish!
waiting for worker thread10 11 to finish!
false
false
waiting for worker thread8 9 to finish!
false
waiting for worker thread4 5 to finish!
false
waiting for worker thread11 12 to finish!
false