import multiprocessing
def foo(i): print('called function in process %s' % i) if name=="main": pros=[] for i in range(5): p=multiprocessing.Process(target=foo,args=(i,)) pros.append(p) p.start() p.join()
线程和进程性能
import multiprocessing import datetime import threading def foo(i): print('called function in process %s' % i) if name=="main": pros=[] starttime = datetime.datetime.now() for i in range(5): p=multiprocessing.Process(target=foo,args=(i,)) pros.append(p) p.start() p.join() endtime = datetime.datetime.now() print((endtime - starttime).microseconds/1000) starttime = datetime.datetime.now() for i in range(5): p = threading.Thread(target=foo, args=(i,)) pros.append(p) p.start() p.join() endtime = datetime.datetime.now() print((endtime - starttime).microseconds / 1000)
called function in process 0 called function in process 1 called function in process 2 called function in process 3 called function in process 4 99.059 called function in process 0 called function in process 1 called function in process 2 called function in process 3 called function in process 4 0.998
获取CPU数量：multiprocessing.cpu_count()
import multiprocessing import time
def process(num): time.sleep(num) print('Process:', num)
if name == 'main': for i in range(5): p = multiprocessing.Process(target=process, args=(i,)) p.start()
代码语言：javascript复制print('CPU number:' str(multiprocessing.cpu_count()))
for p in multiprocessing.active_children():
print('Child process name: ' p.name ' id: ' str(p.pid))
print('Process Ended')继承Process
from multiprocessing import Process import time
class MyProcess(Process): def init(self, loop): Process.init(self) self.loop = loop
代码语言：javascript复制def run(self):
for count in range(self.loop):
time.sleep(1)
print('Pid: ' str(self.pid) ' LoopCount: ' str(count))if name == 'main': for i in range(2, 5): p = MyProcess(i) p.start()
daemon=True 守护进程在主进程结束马上终止，如果daemon=False ，主进程结束也不会结束
from multiprocessing import Process import time import os
def func(num): print(f'{num},pid:{os.getpid()},ppid:{os.getppid()}') while True: print('is alive') time.sleep(0.5)
def wahaha(): i = 0 while i < 5: i = 1 print(f'第{i}秒') time.sleep(1)
if name == 'main': Process(target=wahaha).start() #子进程在主进程结束后仍然正常执行 p = Process(target=func,args=(1,)) p.daemon = True #主进程结束,该守护进程结束 p.start() time.sleep(3) print(f'pid:{os.getpid()},ppid:{os.getppid()}') print('主进程结束')
