dual-core vs. HyperThreading

[Kevin D. Clark]

dan writes:

> A client has some complex simulation/modelling software which runs (a)
> much faster and (b) without bogus results with HT disabled. The
> software vendor says the bogus results are due to their code, not HT
> itself, but HT exposes a flaw in their design. Since the application
> also runs much faster with HT disabled, there's no downside to it in
> that application at least.

For those that might want to get a glimpse into why multithreaded
programming is hard, this paper might be a good read:

  http://www.eecs.berkeley.edu/Pubs/TechRpts/2006/EECS-2006-1.pdf

My favorite part of the paper is here:

   To offer a third analogy, a folk definition of insanity is to do
   the same thing over and over again and to expect the results to be
   different. By this definition, we in fact require that programmers
   of multithreaded systems be insane. Were they sane, they could not
   understand their programs. 

Regards,

--kevin
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