Professional Multicore Programming: Design and Implementation for C++ Developers

Chapter 7. Communication and Synchronization of Concurrent Tasks

	There is only one constant, one universal. It is the only real truth; causality. Action, reaction. Cause and effect.
	--Merovingian, Matrix Reloaded

In Chapter 6, we discussed the similarities and differences between processes and threads. The most significant difference between threads and processes is that each process has its own address space and threads are contained in the address space of their process. We discussed how threads and processes have an id, a set of registers, a state, and a priority, and adhere to a scheduling policy. We explained how threads are created and managed. We also created a thread class.

In this chapter, we take the next step and discuss communication and cooperation between threads and processes. We cover among other topics:

• Communication and cooperation dependencies.

• Interprocess and Interthread Communication.

• The PRAM model and concurrency models.

• Order of execution models.

• Object-oriented message queues and mutexes.

• A simple agent model for a pipeline.

Communication and Synchronization

In Chapter 3, we discussed the challenges of coordinating the execution of concurrent tasks. The example used was software-automated painters who were to paint the house before guests arrived for the holidays. A number of issues were outlined while decomposing of the problem and solution for the purpose of determining what would be the best approach to painting the house. Some of those issues had to deal with ...