When npm installs native node modules it uses
node-gyp to compile code. This is the seam node uses for targeting different operating systems, e.g.
node-gyp compiles using one core and if you have more than one you probably want to utilize that power to speed up compile time. The way
node-gyp handles this is by using the
JOBS environment variable, which sets the
jobs variable here. This piece of code then checks the value of
jobs to determine how many cores to use.
Note that if the value of
max then all cores will be used. So lets try this on
leveldown. First lets check that
JOBS isn't set yet:
lms@ux301|01:34|~/src/leveldb-repos/leveldown (master) $ echo $JOBS