进程同步生产者消费者问题
时间: 2024-06-13 14:06:53 浏览: 137
进程同步生产者消费者问题是指在多进程环境下,生产者和消费者共享同一有界缓冲区,需要通过同步机制来保证生产者和消费者之间的协调和互斥,避免出现数据不一致等问题。
一种解决方案是使用信号量来实现进程同步。具体实现步骤如下:
1. 定义两个信号量empty和full,分别表示缓冲区空闲的空间和缓冲区已经填充的空间。
2. 定义一个互斥信号量mutex,用于保证生产者和消费者之间的互斥访问。
3. 生产者进程首先获取empty信号量,如果缓冲区已满则等待;否则获取mutex信号量,将数据放入缓冲区,释放mutex信号量,增加full信号量。
4. 消费者进程首先获取full信号量,如果缓冲区为空则等待;否则获取mutex信号量,从缓冲区取出数据,释放mutex信号量,减少empty信号量。
5. 在每次生产者或消费者操作后,即时显示有界缓冲区的全部内容,当前指针位置和生产者/消费者线程的标识符。
下面是一个Python实现的示例代码:
```python
import threading
class BoundedBuffer:
def __init__(self, size):
self.size = size
self.buffer = [None] * size
self.mutex = threading.Semaphore(1)
self.empty = threading.Semaphore(size)
self.full = threading.Semaphore(0)
self.read_pos = 0
self.write_pos = 0
def put(self, data):
self.empty.acquire()
self.mutex.acquire()
self.buffer[self.write_pos] = data
self.write_pos = (self.write_pos + 1) % self.size
self.mutex.release()
self.full.release()
def get(self):
self.full.acquire()
self.mutex.acquire()
data = self.buffer[self.read_pos]
self.read_pos = (self.read_pos + 1) % self.size
self.mutex.release()
self.empty.release()
return data
def producer(buffer, id):
for i in range(10):
data = "Producer %d: %d" % (id, i)
buffer.put(data)
print("Producer %d put: %s" % (id, data))
def consumer(buffer, id):
for i in range(10):
data = buffer.get()
print("Consumer %d get: %s" % (id, data))
if __name__ == "__main__":
buffer = BoundedBuffer(5)
producers = [threading.Thread(target=producer, args=(buffer, i)) for i in range(2)]
consumers = [threading.Thread(target=consumer, args=(buffer, i)) for i in range(2)]
for t in producers + consumers:
t.start()
for t in producers + consumers:
t.join()
```