Quote:
Originally Posted by Samurai_Crow
It shouldn't be too surprising. I think Gunnar is figuring out many of the same cache optimizations that are used by Intel. One additional advantage that the '060 and '080 share is that the code density is slightly higher than most of the others.
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I'm not sure code density makes much of a difference for this benchmark. The code is relatively small and should fit in the ICache of all but the oldest processors. The Data takes the same space in the DCache of all processors. Furthermore, if Gunnar cared about code density then maybe he wouldn't have abandoned research and enhancements which improve it.
Quote:
Originally Posted by Samurai_Crow
The AMD64 instruction set brought registers that were only used for segment pointers that hung lifeless in 32-bit enhanced code back into circulation as general-purpose registers bringing the total up to 16. Of course the '080 has an additional bank of 8 bringing the total for the '080 up to 24, as you have probably heard.
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The 68080, as Gunnar calls it, isn't using any of those extra registers for this benchmark. They are unlikely to ever be used by any compiler. This benchmark is testing only the decades old API and stack based ABI of a more modern 68k CPU design. The AMD64/x86_64 enhancements of 64 registers and an improved ABI passing function arguments in registers is being utilized.
Quote:
Originally Posted by TuKo
Thanks for these results, they are very interesting ! Can you please give us model details for Core 2 Duo ?
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Results will vary significantly due to many factors. My point was to produce a rough idea of the peak performance in cache of different processors which is roughly comparable. My numbers and info was based on the web site I linked to (and numbers given in this thread) and I do not know how reliable they are other than the 68060 numbers from my Amiga. There probably is a significant difference between early Core 2 Duos with small caches and later die shrink versions with larger caches. Results can vary significantly by API/ABI used as well. Samurai's results are significantly higher for example. They would be ~3.80 MB/s/MHz. The Core 2 Duo is a strong and efficient (for x86_64 architecture) processor.