Python for循环创建多进程

import threading
 
def ThFun(start, stop):
    print(start, stop)
 
startTime = time.time()
size = 10001	#总任务数
num_p = 5	#进程数
tasks_num = int(size/num_p)	#单个进程的任务数
p = Pool(num_p)
for n in range(0, size, tasks_num):
    stop = n + tasks_num if n + tasks_num <= size else size
    p.apply_async(ThFun, args=[n, stop])
p.close()
p.join()
endTime = time.time()
print(endTime - startTime)

0 2000
2000 4000
4000 6000
6000 8000
8000 10001
2.4579620361328125