Add on-disk binary search benchmark #3
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…with" This reverts commit 0455261.
Kerollmops
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nnethercott
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| let reference = unsafe { s.get_unchecked(mid) }; | ||
| yield prefetch(reference); | ||
| yield mid; |
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Why are you doing a s.get_unchecked(mid) before yielding mid to be prefetched by the kernel ? wouldn't this touch the memory twice ?
[edit]: I tried timing the in_memory benchmark swapping the order of yield mid with let reference = .. and it was a lot slower contrary to my expectations 🧐 why is this the case?
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What get_unchecked is just an offset on top of a pointer, giving you a reference. I return mid to be prefetched later and the reference is dereferenced (read) just after the yield. The memory access (load of page) is done when we dereferenced to read the value. I don't know exactly why inverting the yield and get_reference is slower though 🤔
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