FROM EDN EUROPE: A benchmark for microprocessor power
By Graham Prophet, EDN Europe -- EDN, April 13, 2006
With an increasing number of product designs being power-constrained—whether running from batteries or limited by heat dissipation—the Benchmarking consortium EEMBC has responded to the need to add power to its series of metrics of processor performance. Called EnergyBench, the scheme provides a standardised framework in which users can measure the power demand of a processor while the latter executes EEMBC standard benchmark code.
Unlike almost everything else that EEMBC does, the power measurements are not simulations but are the result of "real-world" tests. The standardisation comes through specifying a consistent model for the measurement hardware, the methods of carrying out the measurements, and the interpretation of the results. EEMBC has formed a partnership with National Instruments, nominating a test-equipment configuration from NI's PXI product range, together with LabView software. Setting up a single instance of the set-up would cost "a few thousand dollars", according to EEMBC's Markus Levy. Levy also notes that these measurements are done in hardware because the detailed simulations required would simply be too difficult and time-consuming: "it has to be real silicon." Users can measure core and I/O power consumption, by adding precision resistors to the processor's power-supply lines. For a given benchmark, the code runs multiple times under controlled conditions, and the software computes an average power for the complete test—this is the energy benchmarks for that processor and software task.
The test suite is in final development, with first results expected at May's Microprocessor Forum meeting; participating EEMBC members include AMD, Freescale, IBM and Analog Devices.
