Per-Application Power Delivery
Akhil Guliani, Michael M. Swift · 2019
Datacenter servers are often under-provisioned for peak power consumption due to the substantial cost of providing power. When there is insufficient power for the workload, servers can lower voltage and frequency levels to reduce consumption, but at the cost of performance. Current processors provide power limiting mechanisms, but they generally apply uniformly to all CPUs on a chip. For servers running heterogeneous jobs, though, it is necessary to differentiate the power provided to different jobs. This prevents interference when a job may be throttled by another job hitting a power limit. While some recent CPUs support per-CPU power management, there are no clear policies on how to distribute power between applications. Current hardware power limiters, such as Intel's RAPL throttle the fastest core first, which harms high-priority applications.