Firestorm: Operating Systems for Power-Constrained Architectures

The phenomenon of Dark Silicon has made processors over-provisioned with compute units that cannot be used at full performance without exceeding power limits. Such limits primarily exist to exercise control over heat dissipation. Current systems support mechanisms to ensure system-wide guarantees of staying within the power and thermal limit. However, these mechanisms are not sufficient to provide process-level control to ensure applications level SLAs: power may be wasted on low-priority applications while high-priority ones are throttled. We built Firestorm, an operating system extension that introduces power and thermal awareness. Firestorm considers power a limited resource and distributes it to applications based on their importance. To control temperature, Firestorm also introduces the notion of thermal capacity as another resource that the OS manages. These abstractions, implemented in Firestorm with mechanisms and policies to distribute power and limit heat production, help applications to achieve guaranteed performance and stay within the system limits. In experiments, we show that Firestorm improved performance by up to 10% by avoiding thermal interference and can guarantee SLAs for soft real time applications in the presence of limited power and competing applications