PABST: Proportionally Allocated Bandwidth at the Source and Target

Abstract

Higher integration lowers total cost of ownership (TCO) in the data center by reducing equipment cost and lowering energy consumption. However, higher integration also makes it difficult to achieve guaranteed quality of service (QoS) for shared resources. Unlike many other resources, memory bandwidth cannot be finely controlled by software in existing systems. As a result, many systems running critical, bandwidth-sensitive applications remain underutilized to protect against bandwidth interference. In this paper, we propose a novel hardware architecture allowing practical, software-controlled partitioning of memory bandwidth. Proportionally Allocated Bandwidth at the Source and Target (PABST) precisely controls the bandwidth of applications by throttling request rates at the source and prioritizes requests at the target. We show that PABST is work conserving, such that excess bandwidth beyond the requested allocation will not go unused. For applications sensitive to memory latency, we pair PABST with a simple priority scheme at the memory controller. We show that when combined, the system is able to lower TCO by providing performance isolation across a wide range of workloads, even when co-located with memory-intensive background jobs.