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SubjectRe: CONUNDRUM.


On Wed, 12 Feb 1997, Ingo Molnar wrote:

>
> > One binary code executes under MSDOS 17% faster(!) than
> > under Linux. Why? How to get this loss back? I was dazed&confused.
>
> one thing: it uses ALOT of floating point. And you say this happens:
>
> [irqs off]
> [timestamp1]
>
> <ALOT of computing, only from memory, into memory, using CPU and FPU>
>
> [timestamp2]
> [irqs on]
>
> and delta := timestamp2-timestamp1, and you say delta(DOS) is 17% better
> than delta(Linux) ?
>
> all code has the same alignment? And it's only this code that is
> executing? And you say TLB cache isnt trashing?

1) Do you have the pentium optimized memcpy installed?
2) Does your system clock keep time properly in both environments?

Y.


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