Performance or Efficiency? A Tale of Two Cores for DB Workloads

We study the performance, power, and thermal profiles for database workloads on hybrid P-core and E-core CPUs. We find that E-cores run cooler than P-cores, use less power, and are more energy-efficient, but need to be provisioned more than 3x the number of P-cores for equivalent performance on multi-threaded analytics workloads. For latency-critical transactional workloads, E-cores can significantly extend very short tail latencies but have less impact for workloads with longer latencies. Asymmetric work distribution policies skewed towards P-cores can improve grouped aggregation performance compared to symmetric policies.