python multiprocessing写生产者和消费者问题

淡淡的烟草味﹌ 2023-06-10 08:26 16阅读 0赞

from time import time
    from time import sleep
    from multiprocessing import Process, Queue
    import multiprocessing as mp
    import random
    
    def get_process_idx():
        return mp.current_process()._identity[0]
    
    def consumer(myqueue):
        for i in range(5):
            result = myqueue.get()
            print('Process{}: consume result:{} '.format(get_process_idx(),result))
            sleep(0.2 * random.random())
    
    
    def producer(myqueue):
        for i in range(5):
            result = random.random()
            myqueue.put(result)
            print('Process{}: produce result:{} '.format(get_process_idx(), result))
            sleep(0.2 * random.random())
    
    
    def main():
      queue = Queue()
      st = time()
      consumer_list = [Process(target=consumer, args=(queue,)) for _ in range(5)] # 5 consumers
      producer_list = [Process(target=producer, args=(queue,)) for _ in range(5)] # 5 producers
      for i in range(5):
          consumer_list[i].start()
          producer_list[i].start()
      sleep(0.5)
      print('The main process can also run!')
      for i in range(5):
          producer_list[i].join()
          consumer_list[i].join()
    
    
    if __name__ == "__main__":
        main()

输出：

Process6: produce result:0.7980437995602082 
    Process1: consume result:0.7980437995602082 
    Process6: produce result:0.6964217548571279 Process1: consume result:0.6964217548571279 
    
    Process7: produce result:0.2978159324178927 
    Process2: consume result:0.2978159324178927 
    Process6: produce result:0.17818916524122852 
    Process6: produce result:0.6029254783995365 
    Process2: consume result:0.17818916524122852 
    Process1: consume result:0.6029254783995365 
    Process2: consume result:0.3600079250057805 
    Process7: produce result:0.3600079250057805 
    Process8: produce result:0.913012046010522 
    Process2: consume result:0.913012046010522 
    Process6: produce result:0.37486844508773387 
    Process3: consume result:0.37486844508773387 
    The main process can also run!
    Process7: produce result:0.39852102716186033 
    Process1: consume result:0.39852102716186033 
    Process8: produce result:0.5478443045458551 
    Process4: consume result:0.5478443045458551 
    Process7: produce result:0.40159627290519384 
    Process1: consume result:0.40159627290519384 
    Process9: produce result:0.10454674925087826 
    Process8: produce result:0.06369777804225396 
    Process3: consume result:0.10454674925087826 
    Process2: consume result:0.06369777804225396 
    Process7: produce result:0.5359514045672161 
    Process4: consume result:0.5359514045672161 
    Process8: produce result:0.47331961869501293 
    Process3: consume result:0.47331961869501293 
    Process9: produce result:0.34366138897147935 
    Process5: consume result:0.34366138897147935 
    Process10: produce result:0.044588902012483 
    Process4: consume result:0.044588902012483 
    Process10: produce result:0.03577255756347597 
    Process9: produce result:0.5750994658950933 
    Process8: produce result:0.13134188773835842 
    Process4: consume result:0.03577255756347597 
    Process3: consume result:0.5750994658950933 
    Process5: consume result:0.13134188773835842 
    Process9: produce result:0.45333928847698013 
    Process4: consume result:0.45333928847698013 
    Process10: produce result:0.3819280323130264 
    Process3: consume result:0.3819280323130264 
    Process9: produce result:0.7451667564233875 
    Process5: consume result:0.7451667564233875 
    Process10: produce result:0.782545501862475 
    Process5: consume result:0.782545501862475 
    Process10: produce result:0.3452227694112342 
    Process5: consume result:0.3452227694112342

看起来生产者和消费者这样交替打印，很大的原因是用了multiprocessing的Queue的get函数，如果队列为空的话，会阻塞，等到有资源的时候才释放，这是进程安全的。不像以前用c写多进程那么蛋疼。