RapidIO: The Next Generation Communication Fabric For Embedded Application

1.2. MULTIPROCESSING

Multiprocessing is increasingly seen as a viable approach to adding more processing capability to a system. Historically multiprocessing was used only in the very highest end computing systems and typically at great cost. However, the continuing advance of semiconductor process technology has made multi-processing a more mainstream technology and its use can offer advantages beyond higher processing performance.

Figure 1.2 is a photograph of a multiprocessing computer system. This computer system uses 76 microprocessors connected together with RapidIO to solve very complex signal processing problems.

Multiprocessing can also be used to reduce cost while achieving higher performance levels. Pricing of processors is often significantly lower for lower-speed parts. The use of multiprocessing may also reduce overall system power dissipation at a given performance point. This occurs because it is often possible to operate a processor at a reduced frequency and achieve a greatly reduced power dissipation. For example, the Motorola 7447 processor has a rated maximum power dissipation of 11.9 W at an operating frequency of 600 MHz. The same processor has a maximum power dissipation of 50 W at an operating frequency of 1000 MHz[1]. If the processing work to be done can be shared by multiple processors, overall power dissipation can be reduced. In this case reducing the frequency by 40% reduces maximum power dissipation by 76%. When performance per watt is an important ...