System-Level Power Analysis of a Multicore Multipower Domain Processor With ON-Chip Voltage Regulators

In this paper, we study two different ON-chip power delivery schemes, namely, fully integrated voltage regulator (FIVR) and low-dropout regulator (LDO), and analyze their effect on total system power under process variation, assuming a realistic dynamic voltage-frequency scaling (DVFS) system. The impact of different task scheduling algorithms on the overall system power was also analyzed. We find that in a hypothetical 256-core processor, under a per-core DVFS assumption, the FIVR-based power delivery consumes 20% less power than the LDO-based one for a 50% throughput. However, as the number of cores in the processor reduces, the difference in power consumption between the FIVR-based and LDO-based power delivery schemes becomes smaller. For example, in the case of a 16-core processor with per-core DVFS capability, FIVR-based design was found to consume about the same power as the LDO-based design.