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verified publisher icon skywind3000

What is the reason of using 256 for prefetchnta?

Open amosbird opened this issue 7 years ago • 2 comments

https://github.com/skywind3000/FastMemcpy/blob/8fea5f666be174c6548d0ae4010e81b0a742c853/FastMemcpy.h#L644

Hi, it bugs me as 128 seems to be a reasonable choice. Is that derived from experiments? Or something related to the mechanism of prefetching itself?

amosbird avatar Aug 27 '18 14:08 amosbird

https://github.com/skywind3000/FastMemcpy/blob/8fea5f666be174c6548d0ae4010e81b0a742c853/FastMemcpy.h#L644

Hi, it bugs me as 128 seems to be a reasonable choice. Is that derived from experiments? Or something related to the mechanism of prefetching itself?

It bugs me too. But I guess it's just an experimental value about how far to look ahead.

zhengle2008 avatar Apr 12 '20 13:04 zhengle2008

https://github.com/skywind3000/FastMemcpy/blob/8fea5f666be174c6548d0ae4010e81b0a742c853/FastMemcpy.h#L644

Hi, it bugs me as 128 seems to be a reasonable choice. Is that derived from experiments? Or something related to the mechanism of prefetching itself?

It bugs me too. But I guess it's just an experimental value about how far to look ahead.

I don't quite understand what the experimental value is in this case. Could you give an example?

ywgrit avatar May 15 '23 08:05 ywgrit