Concurrent Programming

This chapter discusses implementation side of real-time embedded software, with the focus being placed on the mechanisms of intertask synchronization and communication. The chapter gives the POSIX threads, or Pthreads as an example to show the issues and their solutions in concurrent programming. The chapter explains the concepts of race conditions and critical sections and then introduces the various solutions to process synchronization. The mutex, condition variable, and semaphore approaches are only suitable for synchronization between threads of a single process. One way to synchronize data sharing between processes is to use named semaphores. The chapter further introduces widely used real-time signals and timer, and discusses how to use the kernel facilities to implement periodic tasks. A periodic task can be implemented with a process or a thread, depending on the computation complexity of the task.