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SubjectRe: SMP question
J.A. Magallon wrote:
> In short, for FP intensive tasks, hyperthreading is a big lie...
> You can't run 2 computations in parallel.

Yes and no; the benefit of HT depends on the application in question.
I've seen everything from a 5% LOSS in performance to a 30% INCREASE in
performance, for intensive floating-point code. This is with programs
parallelized with OpenMP and Intel's C and Fortran compilers. I'm still
analyzing the exact nature of the benefits, but they *do* exist.

While I much prefer multiple physical CPUs to "virtual" CPUs, HT *does*
provide performance improvements for certain applications. To call HT a
"big lie" is both provacative and inaccurate.

Scott Robert Ladd
Coyote Gulch Productions (

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