PCAP: performance-aware power capping for the disk drive in the cloud

摘要: Power efficiency is pressing in today's cloud systems. Datacenter architects are responding with various strategies, including capping the power available to computing Throttling bandwidth has been proposed cap usage of disk drive. This work revisits throttling and addresses its shortcomings. We show that, contrary common belief, disk's does not always increase as throughput increases. Furthermore, unnecessarily sacrifices I/O response times by idling disk. propose a technique that resizes queues power. Resizing only imposes no delays on servicing requests, but also enables performance differentiation. We present design implementation PCAP, an agile performance-aware system for PCAP dynamically It operates two modes, tail-latency, making it viable systems service-level differentiation. evaluate different workloads drives. Our experiments reduces up 22%. Further, under 60% requests observe service below 100 ms compared just 10% throttling. worst-case latency 50% increases 32% relative