POSIX Threads and Joins – Parallel Programming – PART 1

During a long time we were “blessed” with computers that had only single CPU. The single CPU usually had a mediocre single core and thread. All software developed on that time executed sequential processing.

However, multi-cores and multi-threads processors were introduced in the market but if you do not develop your software trying to explore the hardware advantages your software might have the same performance if running in a single cpu machine.

You need to think also if you software will run in a computer isolated or if your software will be able to run in multiple computers sharing a common network and organize different tasks to resolve a common problem.

Today, I will write this post for my own reference using the POSIX threads and how to have the best usage of joins and mutex implementation. I am running in a ubuntu 10.04 but if you are running Windows you can use these examples installing the POSIX win32 compatibility moduleĀ or installing Cygwin to simulate a linux shell.

Code compilation

All codes on this post were compiled using gcc and invoking the POSIX libraries thru command like under ubuntu 10.04. For example you can use:

gcc -pthread <my source code.c>

Threads

The first code is related to a model where we do not share the same memory space and there is no policy regarding the thread priorities or resources access management (although the threads runs in the same process sharing the same memory space this first example to resource are conflicted).

It is a simple code that creates 3 threads, passes arguments to them using strings and integers and then they are terminated.

Take a look in the code below:

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