GEMS: a new model of parallelism in PC workstations for multimedia applications

This article presents a new model for the exploitation of the different levels of parallelism in general purpose processor based workstations in the framework of multimedia applications. It is called the GEMS model, standing for gain, effort, management and size. It is used to study the intra-processor parallelism including instruction level and data level parallelism, inter-processor parallelism ranging from shared-memory multiprocessors to distributed memory clusters and system level parallelism like input/output operations and the exploitation of external resources. The aim of this work is to help a programmer writing a multimedia application in choosing which level of parallelism will help to speed up the application and how to partition the application into small tasks to obtain the highest gain for a given parallelism. Indeed for an efficient implementation it is very important to have a good understanding of the architecture in order to design new algorithms or to optimize an existing application according to features available in PC workstations