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Kunde21 / markdownfmt

Like gofmt, but for Markdown.
MIT License
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perf: Don't Sprintf for ordered lists #54

Closed abhinav closed 1 year ago

abhinav commented 1 year ago

In order to generate the prefix for ordered lists, listItemMarkerChars currently uses fmt.Sprintf.

fmt.Sprintf("%d%c ", cnt, parList.Marker)

We can make this significantly cheaper by using strconv.AppendInt to convert cnt to a []byte, and appending to that byte slice instead.

Results

Cherry-picking the benchmark from #53, we get the following results with this change:

name                                   old time/op    new time/op    delta
Render/example1.input.md-2               34.2µs ± 0%    33.0µs ± 2%   -3.31%  (p=0.008 n=5+5)
Render/headers.same.md-2                 37.2µs ± 2%    37.4µs ± 4%     ~     (p=0.841 n=5+5)
Render/html.input.md-2                   10.9µs ± 4%    10.8µs ± 1%     ~     (p=0.690 n=5+5)
Render/lists.input.md-2                   139µs ± 3%      91µs ± 1%  -34.64%  (p=0.008 n=5+5)
Render/lists.same.md-2                   47.4µs ± 1%    34.2µs ± 0%  -27.82%  (p=0.008 n=5+5)
Render/nested-code.same.md-2             3.34µs ±26%    3.08µs ± 3%     ~     (p=0.151 n=5+5)
Render/reference.same.md-2                209µs ±27%     192µs ± 5%     ~     (p=0.310 n=5+5)
Render/successive.input.md-2             9.50µs ± 1%    9.41µs ± 1%     ~     (p=0.151 n=5+5)
Render/things-inside-blocks.same.md-2     129µs ± 5%     119µs ± 2%   -8.11%  (p=0.008 n=5+5)
Render/widechar.input.md-2               4.65µs ± 2%    5.05µs ±10%     ~     (p=0.095 n=5+5)

name                                   old alloc/op   new alloc/op   delta
Render/example1.input.md-2               4.39kB ± 0%    4.36kB ± 0%   -0.73%  (p=0.008 n=5+5)
Render/headers.same.md-2                 9.27kB ± 0%    9.27kB ± 0%     ~     (all equal)
Render/html.input.md-2                   2.15kB ± 0%    2.15kB ± 0%     ~     (all equal)
Render/lists.input.md-2                  6.00kB ± 0%    4.82kB ± 0%  -19.61%  (p=0.008 n=5+5)
Render/lists.same.md-2                   2.26kB ± 0%    1.95kB ± 0%  -13.78%  (p=0.008 n=5+5)
Render/nested-code.same.md-2               432B ± 0%      432B ± 0%     ~     (all equal)
Render/reference.same.md-2               25.6kB ± 0%    25.4kB ± 0%   -0.63%  (p=0.008 n=5+5)
Render/successive.input.md-2               520B ± 0%      520B ± 0%     ~     (all equal)
Render/things-inside-blocks.same.md-2    18.3kB ± 0%    18.2kB ± 0%   -0.87%  (p=0.008 n=5+5)
Render/widechar.input.md-2               1.24kB ± 0%    1.24kB ± 0%     ~     (all equal)

name                                   old allocs/op  new allocs/op  delta
Render/example1.input.md-2                  152 ± 0%       148 ± 0%   -2.63%  (p=0.008 n=5+5)
Render/headers.same.md-2                    217 ± 0%       217 ± 0%     ~     (all equal)
Render/html.input.md-2                     30.0 ± 0%      30.0 ± 0%     ~     (all equal)
Render/lists.input.md-2                     749 ± 0%       547 ± 0%  -26.97%  (p=0.008 n=5+5)
Render/lists.same.md-2                      264 ± 0%       210 ± 0%  -20.45%  (p=0.008 n=5+5)
Render/nested-code.same.md-2               14.0 ± 0%      14.0 ± 0%     ~     (all equal)
Render/reference.same.md-2                  932 ± 0%       908 ± 0%   -2.58%  (p=0.008 n=5+5)
Render/successive.input.md-2               39.0 ± 0%      39.0 ± 0%     ~     (all equal)
Render/things-inside-blocks.same.md-2       658 ± 0%       632 ± 0%   -3.95%  (p=0.008 n=5+5)
Render/widechar.input.md-2                 29.0 ± 0%      29.0 ± 0%     ~     (all equal)

Since this change affects ast.ListItem only, that's where the bulk of the performance improvements are.