from multiprocessing import Queue, Process, Pool
import random
import time

parameters=range(10)
ncpu=2

def calculate(par):
        # Do stuff
    time.sleep(5*random.random()) # Randomize writting times.
    savingfile.write(result)
    print result

if __name__=="__main__":
    print 'Started!'

    with open('myfile.txt', 'w', buffering=0) as savefile:
        print 'Launched!'

        pool = Pool(processes=min(ncpu, len(parameters)))
        pool.map_async(calculate, parameters, chunksize=1)
        pool.close()
        pool.join()

    print 'End!'