What is the appropriate number of Gunicorn workers for each Amazon Instance Type?

Question

I'm currently trying to figure out what the appropriate number of workers is for each Amazon Instance Type. I used to run one Gunicorn worker, however that proved to be quite slow.

Many developers are currently using this formula to gauge how many workers would be suitable:

NUM_WORKERS=3  #recommended formula here is 1 + 2 * NUM_CORES

The problem I'm having is that Amazon isn't quite clear as to the number of cores each instance is running. For example, an M1 Small Instance has 1 EC2 Compute Unit (1 virtual core with 1 EC2 Compute Unit)

What does that essentially mean? That it has one core? or that it has two cores?

Answer 1

A simple one-liner solution to return the number of CPU cores:

gunicorn --workers=$((2 * $(getconf _NPROCESSORS_ONLN) + 1)) wsgi:application