Being new to the world of multi-core processors, I always wondered what the true potential of these new chips really was. Before I purchased mine, I did some research into applications that utilise these new features, and found the information was not readily available. Therefore I decided to write a quick guide, and maybe encourage people to use the full potential of their new investment.

First of all it's important to understand what a multi-threaded application really is. By definition, it is a piece of software that is aware of more than one core/processor, and can use these to be able to simultaneously complete multiple tasks. A common mis-conception is that single-core systems are not able to multi-thread. In reality, they are simply performing multi-tasking among multiple threads or programs. But this in itself can cause problems, because many threads are sharing the same hardware resource, and so slow each thread down individually.

And so the multi-core processor was born, allowing a system to give full core support to a single thread. This not only allows multiple single threaded applications to be run at the same time, but also for the mentioned multi-threaded software to be used. Now being able to use multiple cores for a single application will require software to be coded specifically for this task. I have attempted in someway to explain multi-threading in a simple, yet concise way, using some analogies (Where the bank represents the processor, the clients represent the threads within a program or in different programs, and the queues ... well the queue for processor time.)...

A single-threaded program

Imagine a bank, with one cashier and one queue. A customer walks in, and walks straight to the cashier, and they begin serving the customer. A second customer walks in, and is forced to join the queue. He or she complains that they are unhappy with the service, and protests to the cashier that they want to be served. The cashier has rono choice but to ask the first customer to wait, while he serves the other customer. The original customer then has to wait until the other customer has finished before he or she can continue being served, meaning he or she not only has to wait, but has to waste time by getting out and arranging all the documents he or she has brought with them. It is simply inefficient management.

A multi-threaded program

Imagine the same bank, but this time there is two cashiers. The first client is being served, and the second client walks into the branch. Instead of joining the queue for the first cashier, the second client walks over to the second cashier, and serves him or her. In this case, both clients are able to be served simultaneously, and without effecting the efficiency or time it takes for each client to be completely serviced.

Examples

What follows are some example applications, with a brief analysis of each.