Implement wc fast paths that skip Unicode decoding.#3740
Merged
sylvestre merged 2 commits intouutils:mainfrom Jul 25, 2022
Merged
Implement wc fast paths that skip Unicode decoding.#3740sylvestre merged 2 commits intouutils:mainfrom
sylvestre merged 2 commits intouutils:mainfrom
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Contributor
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@resistor good job, but needs a cargo fmt run ;) |
Byte, character, and line counting can all be done on the raw bytes of the incoming stream without decoding the Unicode characters. This fact was previously exploited in specific fast paths for counting characters and counting lines. This change unifies those fast paths into a single shared fast paths, using const generics to specialize the function for each use case. This has the benefit of making sure that all combinations of these Unicode-oblivious fast paths benefit from the same optimization. On my laptop, this speeds up `wc -clm odyssey1024.txt` from 840ms to 120ms. I experimented with using a filter loop for line counting, but continuing to use the bytecount crate came out ahead by a significant margin.
Contributor
Author
Done |
Contributor
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the coverage indicates that we are missing some tests, could you please add them ? |
Contributor
Author
Done |
Contributor
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@sylvestre this is now good to merge (tail-related failures) ;) |
Contributor
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indeed, thanks :) |
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Byte, character, and line counting can all be done on the raw bytes
of the incoming stream without decoding the Unicode characters. This
fact was previously exploited in specific fast paths for counting
characters and counting lines. This change unifies those fast paths into
a single shared fast paths, using const generics to specialize the
function for each use case. This has the benefit of making sure that all
combinations of these Unicode-oblivious fast paths benefit from the same
optimization.
On my laptop, this speeds up
wc -clm odyssey1024.txtfrom 840ms to120ms. I experimented with using a filter loop for line counting, but
continuing to use the bytecount crate came out ahead by a significant
margin.