add multi-process

Author: michaelliao

py3/multitask/do_folk.py

@@ -0,0 +1,12 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+import os
+
+print('Process (%s) start...' % os.getpid())
+# Only works on Unix/Linux/Mac:
+pid = os.fork()
+if pid == 0:
+    print('I am child process (%s) and my parent is %s.' % (os.getpid(), os.getppid()))
+else:
+    print('I (%s) just created a child process (%s).' % (os.getpid(), pid))

py3/multitask/do_queue.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+from multiprocessing import Process, Queue
+import os, time, random
+
+# 写数据进程执行的代码:
+def write(q):
+    print('Process to write: %s' % os.getpid())
+    for value in ['A', 'B', 'C']:
+        print('Put %s to queue...' % value)
+        q.put(value)
+        time.sleep(random.random())
+
+# 读数据进程执行的代码:
+def read(q):
+    print('Process to read: %s' % os.getpid())
+    while True:
+        value = q.get(True)
+        print('Get %s from queue.' % value)
+
+if __name__=='__main__':
+    # 父进程创建Queue，并传给各个子进程：
+    q = Queue()
+    pw = Process(target=write, args=(q,))
+    pr = Process(target=read, args=(q,))
+    # 启动子进程pw，写入:
+    pw.start()
+    # 启动子进程pr，读取:
+    pr.start()
+    # 等待pw结束:
+    pw.join()
+    # pr进程里是死循环，无法等待其结束，只能强行终止:
+    pr.terminate()

py3/multitask/multi_processing.py

@@ -0,0 +1,17 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+from multiprocessing import Process
+import os
+
+# 子进程要执行的代码
+def run_proc(name):
+    print('Run child process %s (%s)...' % (name, os.getpid()))
+
+if __name__=='__main__':
+    print('Parent process %s.' % os.getpid())
+    p = Process(target=run_proc, args=('test',))
+    print('Child process will start.')
+    p.start()
+    p.join()
+    print('Child process end.')

py3/multitask/pooled_processing.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+from multiprocessing import Pool
+import os, time, random
+
+def long_time_task(name):
+    print('Run task %s (%s)...' % (name, os.getpid()))
+    start = time.time()
+    time.sleep(random.random() * 3)
+    end = time.time()
+    print('Task %s runs %0.2f seconds.' % (name, (end - start)))
+
+if __name__=='__main__':
+    print('Parent process %s.' % os.getpid())
+    p = Pool(4)
+    for i in range(5):
+        p.apply_async(long_time_task, args=(i,))
+    print('Waiting for all subprocesses done...')
+    p.close()
+    p.join()
+    print('All subprocesses done.')