Add specialized SIMD line seeking routines #408
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DHowett
reviewed
Jun 3, 2025
src/buffer/mod.rs
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| @@ -1229,7 +1229,7 @@ impl TextBuffer { | |||
| } | |||
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| let (delta, line) = | |||
| unicode::newlines_backward(chunk, chunk.len(), result.logical_pos.y, y); | |||
| simd::lines_bwd(chunk, chunk.len(), result.logical_pos.y, result.logical_pos.y); | |||
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this seems like an important change - arg 4?
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I forgot to push before opening the PR. 😅
DHowett
reviewed
Jun 3, 2025
src/simd/lines_bwd.rs
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| /// seeks backwards even if the `line` is already at `line_stop`. | ||
| /// This allows you to ensure (or test) whether `offset` is at a line start. | ||
| /// | ||
| /// It returns an offset *past* the newline (= at the start of the next line). |
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next -> previous?
Suggested change
| /// It returns an offset *past* the newline (= at the start of the next line). | |
| /// It returns an offset *past* the newline (= at the start of the prior line). |
or perhaps I misunderstand
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It's more like "the current line". I changed the wording a bit to be clearer about this.
DHowett
approved these changes
Jun 5, 2025
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The previous
memchrloop had the fatal flaw that it would break outof the SIMD routines every time it hit a newline. This resulted in a
throughput drop down to ~250MB/s on my system in the worst case.
By writing SIMD routines specific to newline seeking, we can bump
that up by >500x. Navigating through a 1GB of text now takes ~16ms
independent of the contents.