python 歸納 (十一)_線程_threading.Thread

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總結:

1. 預設父線程跑完,子線程並不會馬上退出,不像 thread.start_threadXXXX
2. 父線程跑完了，並沒有退出，一直在那裡
3. 線程啟動速度很快，不佔多少開銷，不到1毫秒

代碼:

# -*- coding: utf-8 -*-"""學習 並發linux下執行"""from threading import Threadfrom multiprocessing import Processimport timeimport osimport psutildef work():    print(‘%s,%f: sub begin %d‘ % (time.strftime(‘%M:%S‘,time.localtime(time.time())),time.time(),os.getpid()))    print "%s,%f: sub %d,%d,%d" % (time.strftime(‘%M:%S‘,time.localtime(time.time())),time.time(),os.getpid(),os.getppid(), psutil.Process(os.getpid()).num_threads())    time.sleep(5)    print "%s,%f: sub %d,%d,%d" % (time.strftime(‘%M:%S‘,time.localtime(time.time())),time.time(),os.getpid(),os.getppid(), psutil.Process(os.getpid()).num_threads())    print(‘%s,%f: sub end %d‘ % (time.strftime(‘%M:%S‘,time.localtime(time.time())),time.time(),os.getpid()))if __name__ == ‘__main__‘:    print "%s,%f: main begin" % (time.strftime(‘%M:%S‘,time.localtime(time.time())),time.time())    print "%s,%f: main %d,%d,%d" % (time.strftime(‘%M:%S‘,time.localtime(time.time())),time.time(),os.getpid(),os.getppid(), psutil.Process(os.getpid()).num_threads())    # 開啟子線程    t=Thread(target=work)    t.start()    print  ‘%s,%f: main 線程‘ %  (time.strftime(‘%M:%S‘,time.localtime(time.time())),time.time())    print "%s,%f: main %d,%d,%d" % (time.strftime(‘%M:%S‘,time.localtime(time.time())),time.time(),os.getpid(),os.getppid(), psutil.Process(os.getpid()).num_threads())    # 開啟子進程    # t=Process(target=work)    # t.start()    # print "\nmain %d,%d,%d" % (os.getpid(),os.getppid(), psutil.Process(os.getpid()).num_threads())    # print(‘\nmain 進程‘)    print "%s,%f: main end" % (time.strftime(‘%M:%S‘,time.localtime(time.time())),time.time())

　　

輸出：

格式說明：

小時 :秒，時間戳記,     <當前進程ID,  [父 進程ID,當前進程線程數量]>

[email protected]:~/python# python test_threadprocess1.py

----------------------------------------------------------

03:04,1536397384.349529: main begin
03:04,1536397384.349605: main 3604,2692,1
03:04,1536397384.350838: sub begin 3604
03:04,1536397384.350939: main 線程
03:04,1536397384.351009: sub 3604,2692,2
03:04,1536397384.351310: main 3604,2692,2
03:04,1536397384.352097: main end
03:09,1536397389.357353: sub 3604,2692,2   

03:09,1536397389.358372: sub end 3604

----------------------------------------------------------

輸出解讀:

1. 黃色 標記的中間 輸出部分 ，是啟動 子線程期間，這段 時間非常快，說明啟動線程的速度很快
2. 紅色標記，此時main線程的邏輯 代碼跑完了，但是還是顯示有2個線程，對比開始，說明main線程並 沒有退出 

 

python 歸納 (十一)_線程_threading.Thread