t.py

import os
import time
import gevent


def f(x):
    gevent.sleep(1)


def main():
    print 'pid =', os.getpid()
    print 'spawn...'
    jobs = []
    for y in xrange(5):
        for x in xrange(10**5):
            jobs.append(gevent.spawn(f, x))
        gevent.sleep(2)
    print 'done spawning'
    # loop infinitely
    while True:
        if jobs is not None and all([job.ready() for job in jobs]):
            gevent.joinall(jobs)
            print 'all jobs completed'
            jobs = None
            return 'Done'
        gevent.sleep(2)

# Join
gevent.joinall([gevent.spawn(main)])

while True:
  time.sleep(1)
  print('Finished')

t_bad.py

import os
import time
import gevent


def f(x):
    gevent.sleep(1)


def main():
    print 'pid =', os.getpid()
    print 'spawn...'
    jobs = []
    for y in xrange(5):
        for x in xrange(10**5):
            jobs.append(gevent.spawn(f, x))
        gevent.sleep(2)
    print 'done spawning'
    # loop infinitely
    while True:
        if jobs is not None and all([job.ready() for job in jobs]):
            #gevent.joinall(jobs)
            print 'all jobs completed'
            jobs = None
            #return 'Done'
        gevent.sleep(2)

# Join
gevent.joinall([gevent.spawn(main)])

while True:
  time.sleep(1)
  print('Finished')