= John D. McCalpin
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<John D. McCalpin> developed <STREAM>, a benchmark for sustained <memory bandwidth> using simple operations on large arrays. His reference documentation specifies both execution rules and how the benchmark counts transferred bytes and arithmetic work, making reported rates interpretable.<STREAM Benchmark Reference Information by John D. McCalpin>[What is STREAM?, Run Rules and byte/FLOP table]{ref}
For the triad operation $a_i=b_i+s c_i$ on eight-byte values, the conventional accounting counts two reads and one write: 24 bytes per element, with two floating-point arithmetic operations. A measured rate of $24\,\mathrm{GB\,s^{-1}}$ therefore corresponds to $10^9$ processed elements per second under that accounting. Actual memory-bus traffic can differ because of cache and write policies. The measurement targets data movement through a specified workload, rather than assuming that peak arithmetic throughput predicts application speed.
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{title=Portrait of <John D. McCalpin>}
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