The Pleiades Architecture
Rapid advances in portable computing and communication devices require implementations that must not only be highly energy efficient, but they must also be flexible enough to support a variety of multimedia services and communication capabilities. The required flexibility dictates the use of programmable processors in implementing the increasingly sophisticated digital signal processing algorithms that are widely used in portable multimedia terminals. However, compared to custom, application-specific solutions, programmable processors often incur significant penalties in energy efficiency and performance. The architectural approach presented in this chapter involves trading off flexibility for increased efficiency. This approach is based on the observation that for a given domain of signal processing algorithms, the underlying computational kernels that account for a large fraction of execution time and energy are very similar. By executing the dominant kernels of a given domain of algorithms on dedicated, optimized processing elements that can execute those kernels with a minimum of energy overhead, significant energy savings can potentially be achieved. Thus, this approach yields processors that are domain-specific.
In this chapter, a reusable architecture template (or platform), named Pleiades [1,2], that can be used to implement domain-specific, programmable processors ...