Thesis Defense - Ghiasi

Power consumption and thermal dissipation are becoming critical design constraints as processors continue to become more complex and are implemented in denser technologies. As this trend continues, the contribution of static power consumption to overall power consumption continues to rise and is expected to surpass dynamic power consumption within a few process generations. Thermal densities are also rising. The combination of rising static power and thermal density exposes a feedback loop between the two that can cause unmanageable temperatures.

Many applications do not require the full processing power of modern chips. The question then arises of how designers of modern processors can take into account the needs of applications that require the full processing power of modern designs and those that don't. Techniques ranging from voltage scaling to complexity effective design have been proposed to address these issues.

This work explores an alternative, Aide de Camp, that uses an asymmetric multi-core design. I argue that Aide de Camp can provide nearly the same performance as a more complex modern processor, but with considerably less power consumption and heat dissipation. It provides a mechanism to improve performance over a single core when all cores are scheduled simultaneously. It also provides a technique to deal with thermal overload situations. Finally, it provides an alternative to existing complexity effective designs.

This thesis examines the design space of asymmetric multi-core designs and the effect of various design decisions on the performance, energy consumption and practicality of asymmetric multi-core design. The potential of Aide de Camp to save energy as well as increase processing capabilities is demonstrated and compared to a modern dual core processor. A variety of thermal techniques are explored and compared to existing single core thermal techniques.