An adaptive chip-multiprocessor architecture for future mobile terminals

Mladen Nikitovic, Mats Brorsson
2002 Proceedings of the international conference on Compilers, architecture, and synthesis for embedded systems - CASES '02  
Power consumption has become an increasingly important factor in the field of computer architecture. It affects issues such as heat dissipation and packaging cost, which in turn affects the design and cost of a mobile terminal. Today, a lot of effort is put into the design of architectures and software implementation to increase performance. However, little is done on a system level to minimize power consumption, which is crucial in mobile systems. We propose an adaptive chip-multiprocessor
more » ... ) architecture, where the number of active processors is dynamically adjusted to the current workload need in order to save energy while preserving performance. The architecture is suitable in future mobile terminals where we anticipate a bursty and performance demanding workload. We have carried out an evaluation of the performance and power consumption of the proposed architecture using previously validated high-level simulation models. Our experiments show that orders of magnitude in power consumption can be saved compared to a conventional architecture to a negligable performance cost. The method used is complementary to other power saving techniques such as voltage and frequency scaling. A common way of using parallelism in high-performance computers is to utilize the available instruction-level parallelism (ILP) in the applications. This is a hardware-intensive approach to improved performance and gives diminishing returns making it unsuitable in embedded mobile systems [15] . A more promising approach to achieve high system performance is to utilize the available thread-level parallelism (TLP) which we believe will be common in systems we are considering. With several processors on one chip we can build a chip-multiprocessor (CMP) that can easily scale performance efficiently. However, the increased performance can cause the power consumption of the system to increase if no effort is put into making it energy-efficient. A device uses energy by consuming power statically and dynamically. Dynamic power is consumed due to switching of transistors and short circuit currents during transistor switches (eq. 1). Static power is consumed due to leakage currents dissipated from the Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee.
doi:10.1145/581636.581638 fatcat:pplg744ocnhtvizu32iab6jgp4