Benchmarks come with additional energy data

A new standard provides data on the amount of energy a processor consumes while running EEMBC's performance benchmarks.

The Embedded Microprocessor Benchmark Consortium (EEMBC) has published the first certified embedded processor benchmark scores using EnergyBench, a new standard that provides data on the amount of energy a processor consumes while running EEMBC's performance benchmarks.

The device benchmarked for these landmark scores is the 500-MHz AMD Geode LX800@0.9W processor, which was tested in an out-of-the-box environment simultaneously with EnergyBench and ConsumerBench Version 1.1, an EEMBC benchmark suite that allows users to approximate the performance of processors in digital still cameras, printers, and other embedded systems that handle digital imaging tasks.

Across the ConsumerBench battery of tests, performance results for the AMD Geode LX800@0.9W processor ranged from 18 iterations per second for JPEG compression to 204 iterations per second for RGB-to-CMYK conversion, while the EnergyBench scores for each of the kernels indicated an average power consumption range of 2.34W (for RGB-to-YIQ conversion) to 2.58W (for JPEG decompression).

Overall, the results show that the power consumed by the processor depended on what workload the processor was handling and that this could vary within the ConsumerBench tests by as much as 10%.

"As a metric, EnergyBench will be most useful when we are able to compare results from multiple processors side by side, but these results for the AMD Geode LX processor are sufficient to demonstrate the rationale behind EnergyBench - namely that there is no such thing as 'typical' power consumption", said Markus Levy, EEMBC President.

"This fact won't come as news to veteran systems designers, but now they'll have a tool that will help them avoid any surprises about the power consumption behaviour of embedded processors in situ".

The AMD Geode LX800@0.9W processor is specifically designed to provide a high level of performance with low power consumption.

Typical applications include small form-factor products such as thin clients, interactive set-top boxes, single-board computers (SBCs), personal access devices (PADs), and mobile Internet and entertainment devices.

"It is fitting that the AMD Geode LX800@0.9W processor should be the first embedded processor to be tested with EnergyBench, since this processor family was designed from the ground up to enable both high performance and low power consumption", said Erik Salo, Director of AMD's Embedded Computing Solutions Division.

"The EEMBC ConsumerBench and EnergyBench scores clearly demonstrate the excellent performance per watt offered by AMD Geode LX processors".

EEMBC has implemented EnergyBench using the LabView platform and a data acquisition (DAQ) card, both from National Instruments.

While the performance benchmarks are running on the target board, EnergyBench calculates the average energy per iteration using multiple unaliased sampling frequencies and an adaptive statistical process.

The DAQ card samples the voltage levels as well as a trigger channel and writes the samples to a file.

The result of the EnergyBench test is the average energy for one iteration of the workload represented by the performance benchmark kernel running on the target.

Users can also use the EEMBC setup to examine minimum and maximum power while the benchmark is running.

A detailed ConsumerBench score report for the AMD Geode LX800@0.9W processor, which has been verified and certified by the EEMBC Technology centre, is available for free from the EEMBC website.

EnergyBench is available for licence in conjunction with any EEMBC performance benchmark suite.

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