Producer–consumer problem

wikipedia Producer–consumer problem

Without semaphores or monitors

The producer–consumer problem, particularly in the case of a single producer and single consumer, strongly relates to implementing a FIFO or a channel. The producer–consumer pattern can provide highly efficient data communication without relying on semaphores, mutexes, or monitors for data transfer. The use of those primitives can be expansive in terms of performance, in comparison to basic read/write atomic operation. Channels and FIFOs are popular just because they avoid the need for end-to-end atomic synchronization. A basic example coded in C is shown below.

NOTE: lock-free

1、Atomic read-modify-write access to shared variables is avoided, as each of the two Count variables is updated only by a single thread. Also, these variables support an unbounded number of increment operations; the relation remains correct when their values wrap around on an integer overflow.

2、This example does not put threads to sleep, which may be acceptable depending on the system context. The schedulerYield() is inserted as an attempt to improve performance, and may be omitted. Thread libraries typically require semaphores or condition variables to control the sleep/wakeup of threads. In a multi-processor environment, thread sleep/wakeup would occur much less frequently than passing of data tokens, so avoiding atomic operations on data passing is beneficial.

cornell cs3110 Lecture 18: Concurrency—Producer/Consumer Pattern and Thread Pools

Implementation

C++

A C++ Producer-Consumer Concurrency Template Library

Eiffel

https://www.eiffel.org/doc/solutions/Producer-consumer

Java

https://www.geeksforgeeks.org/producer-consumer-solution-using-threads-java/