SOLVING PRODUCER/CONSUMER PROBLEM

USING INTER-THREAD COMMUNICATION

Presented by:

A P S SubashB.Tech, II Year.DEPT. OF COMPUTER SCIENCE AND ENGG.SWARNANDHRA COLLEGE OF ENGG&TECHNARSAPUR, ANDHRA PRADESH

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Contents What is producer/consumer problem ?

Solution for producer/consumer problem.

What is inter-thread communication ?

What are wait(), notify() and notifyAll()

Working of Interthread Communication

Applications

Conclusion

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What is producer/consumer problem ?

In computing , the producer–consumer problem is a classic example of a multi-process synchronization problem.

Here, the problem describes two threads: one is the producer and other one is the consumer. These two threads share a common, fixed-size buffer used as a queue.

The producer's job is to generate data, put it into the buffer, and start again. At the same time, the consumer is consuming the data (i.e., removing it from the buffer), one piece at a time.

The problem is to make sure that - The producer won't try to add data into the buffer if it's full.

- And the consumer won't try to remove data from an empty buffer.

Pictorial representation of producer/consumer problem

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What is the solution ? The solution for the producer is to either go to sleep or discard

data if the buffer is full.

The next time the consumer removes an item from the buffer, it notifies the producer, who starts to fill the buffer again.

In the same way, the consumer can go to sleep if it finds the buffer to be empty.

The next time the producer puts data into the buffer, it wakes up the sleeping consumer.

The solution can be reached by means of ”Inter-thread communication”.

An inadequate solution could result in a deadlock where both threads are waiting to be awakened.

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What is inter-thread communication ?

Inter-thread Communication is a mechanism by which two or more threads communicate smoothly with each other by way of sending and receiving messages among them.

Inter-thread Communication is an elegant mechanism which will be used to solve producer/consumer problem efficiently through the use of the following methods of Object class :

(1) wait() (2) notify()

(3) notifyAll()

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What are wait(), notify(), notifyAll() methods ? wait() tells the calling thread to give up the

monitor and go to sleep until some other thread enters the same monitor and calls notify() or notifyAll().

  notify() wakes up a thread that called wait()

on the same object.  notifyAll() wakes up all the threads that

called wait() on the same object. One of the threads will be granted access.

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Working of Inter-thread Communication

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Applications Producer/Consumer model is used in parallel

computing. Producer/Consumer model is key model for

threads programming, especially for the Pool of Threads model.

It is used for synchronization of concurrently running processes.

It is used in real-time critical applications with multi-Tasking.

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Program output without using ITC

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Program output using ITC

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Conclusion This presentation proved programmatically

that the producer/consumer problem can be effectively solved with the help of Inter-thread Communication. Inter-thread Communication successfully solves the problem by ensuring that:

- the producer won't try to add data into the buffer if it's full. - and the consumer won't try to remove data from an empty buffer.

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