SPEC unveils power consumption benchmark for servers

SPECpower_ssj2008 reports power consumption for servers at different performance levels — from 100-percent to idle in 10-percent segments — over a set period of time. The graduated workload recognizes the fact that processing loads and power consumption on servers vary substantially over the course of days or weeks. To compute a power-performance metric across all levels, measured transaction throughputs for each segment are added together, then divided by the sum of the average power consumed for each segment. The result is a figure of merit called "overall ssj_ops/watt."

The benchmark workload represents typical server-side Java business applications. The workload is scalable, multi-threaded, portable across a wide range of operating environments, and economical to run. It exercises CPUs, caches, memory hierarchy, and the scalability of shared memory processors (SMPs), as well as implementations of the Java Virtual Machine (JVM), JIT (just in time) compiler, garbage collection, threads, and some aspects of the operating system.

The minimum equipment for SPEC-compliant testing is two networked computers, plus a power analyzer and a temperature sensor. One computer is the system under test (SUT), the other a controller system where power, performance and temperature are captured for reporting. A typical test run for SPECpower_ssj2008 takes about 70 minutes using default settings.