opteron VS Itanium 2 (Benchmark cheating)
jcownie at etnus.com
Fri Oct 31 12:10:31 EST 2003
> From way back with early linpack, this has left many benchmarks
> susceptible to vendor manipulation -- there are cases on record of
> vendors (DEC, IIRC, but likely others) actually altering CPU/memory
> architecture to optimize linpack performance because linpack was
> what sold their systems.
This certainly applied to some compilers which "optimized" sdot and
ddot by recognizing the source (down to the precise comments) and
plugged in a hand coded assembler routine.
Changing a comment (for instance mis-spelling Jack's name :-) or
replacing a loop variable called "i" with one called "k" could halve
the linpack result.
When $$$ are involved people are prepared to sail close to the wind...
James Cownie <jcownie at etnus.com>
Etnus, LLC. +44 117 9071438
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