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?
I know this is a old question. But I think I have a better answer to this question. Gunicorn docs suggests that 2n+1 [gunicorn -w <2n+1> myapp:wsgi] is a good guess for number of workers (Yes, n = number of cores). I came up with a tiny shell script to apply this formula. All you need to do is this:
gunicorn -w $(( 2 * `cat /proc/cpuinfo | grep 'core id' | wc -l` + 1 )) myapp:wsgi
Where the command
cat /proc/cpuinfo | grep 'core id' | wc -l
will return the total number of actual CPU cores (n). So
$(( 2 * `cat /proc/cpuinfo | grep 'core id' | wc -l` + 1 ))
equates to 2n+1 formula.
This will apply 2n+1 formula to all the linux-based machines. You dont need to know the number of workers for each type of instance or anything like that.
Reference: http://dhilipsiva.com/2015/10/22/appropriate-number-of-gunicorn-workers.html