t.py

from time import sleep, time
from threading import Thread

class Worker(Thread):

    def run(self):
        count = 0
        while True:
            print "worker says hi. %r" % time()
            sleep(0.1)


w = Worker()
w.daemon = True
w.start()

count = 0
while True:
    print "main says hi. %r" % time()
    count += 1
    if count < 10:
        sleep(0.08)