DIEF: An accurate interference feedback mechanism for chip multiprocessor memory systems

Abstract

Chip Multi-Processors (CMPs) commonly share hardware-controlled on-chip units that are unaware that memory requests are issued by independent processors. Consequently, the resources a process receives will vary depending on the behavior of the processes it is co-scheduled with. Resource allocation techniques can avoid this problem if they are provided with an accurate interference estimate. Our Dynamic Interference Estimation Framework (DIEF) provides this service by dynamically estimating the latency a process would experience with exclusive access to all hardware-controlled, shared resources. Since the total interference latency is the sum of the interference latency in each shared unit, the system designer can choose estimation techniques to achieve the desired accuracy/complexity trade-off. In this work, we provide high-accuracy estimation techniques for the on-chip interconnect, shared cache and memory bus. This DIEF implementation has an average relative estimate error between -0.4% and 4.7% and a standard deviation between 2.4% and 5.8%. © 2010 Springer-Verlag.