Only 4 cores used by default on 8 core machine

[stevage]

Not sure if this is a bug, user error, a documentation issue... I installed from source a few days ago [commit 2fe69d4 ] and found only 4 cores on an 8 core VM were being used (total user CPU% was around 48-49%). From some random googling, I discovered this environment variable:

export UV_THREADPOOL_SIZE=12

(I gather the right number of threads is cores x 1.5) Once set, CPU usage went to nearly 100%.

Node is reporting the number of cpu's correctly:

$ node
> require('os').cpus().length
8

This is an Ubuntu Quantal VM running on openstack.

[springmeyer]

thanks for catching this. Had done this for TM2 (mapbox/mapbox-studio-classic#16), but forgot to apply for TileMill proper.