Optimize out some read operations from the quick deflate algorithm #374

brian-pane · 2025-05-28T17:33:17Z

No description provided.

brian-pane · 2025-05-28T17:34:16Z

Before and after:

Benchmark 1 (69 runs): ./blogpost-compress-baseline 1 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time          73.2ms ± 1.03ms    72.3ms … 79.6ms          4 ( 6%)        0%
  peak_rss           26.6MB ± 63.9KB    26.4MB … 26.7MB          1 ( 1%)        0%
  cpu_cycles          282M  ± 1.17M      280M  …  289M           1 ( 1%)        0%
  instructions        549M  ±  441       549M  …  549M           1 ( 1%)        0%
  cache_references    266K  ± 11.4K      261K  …  331K           5 ( 7%)        0%
  cache_misses        232K  ± 8.08K      206K  …  244K           8 (12%)        0%
  branch_misses      2.88M  ± 8.15K     2.87M  … 2.91M           3 ( 4%)        0%
Benchmark 2 (72 runs): ./target/release/examples/blogpost-compress 1 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time          69.7ms ±  440us    69.0ms … 70.8ms          2 ( 3%)        ⚡-  4.7% ±  0.4%
  peak_rss           26.6MB ± 67.4KB    26.5MB … 26.7MB          0 ( 0%)          -  0.0% ±  0.1%
  cpu_cycles          267M  ±  720K      265M  …  269M           1 ( 1%)        ⚡-  5.2% ±  0.1%
  instructions        522M  ±  233       522M  …  522M           1 ( 1%)        ⚡-  4.9% ±  0.0%
  cache_references    266K  ± 7.48K      261K  …  313K          11 (15%)          -  0.3% ±  1.2%
  cache_misses        231K  ± 8.70K      205K  …  240K           8 (11%)          -  0.3% ±  1.2%
  branch_misses      2.85M  ± 10.9K     2.83M  … 2.87M           0 ( 0%)          -  1.1% ±  0.1%

codecov · 2025-05-28T17:34:34Z

Codecov Report

All modified and coverable lines are covered by tests ✅

Flag	Coverage Δ
fuzz-compress	`?`
fuzz-decompress	`?`
test-aarch64-apple-darwin	`93.38% <100.00%> (-0.01%)`	⬇️
test-x86_64-apple-darwin	`91.69% <100.00%> (+<0.01%)`	⬆️
test-x86_64-unknown-linux-gnu	`90.47% <100.00%> (+<0.01%)`	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
zlib-rs/src/deflate/algorithm/quick.rs	`96.77% <100.00%> (-0.91%)`	⬇️
zlib-rs/src/deflate/hash_calc.rs	`100.00% <100.00%> (ø)`

... and 5 files with indirect coverage changes

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brian-pane · 2025-05-28T17:38:05Z

This is an idea I've been thinking about for a while. It's possible, but complicated, to do this with the higher compression levels, so I started with the simpler deflate_quick to try out the concept.

folkertdev

Wow, that's awesome. Left a comment below to mitigate the effects on other compression levels (they all use the same hashing function, so it's a good idea to check them too)

folkertdev · 2025-05-28T18:24:31Z

zlib-rs/src/deflate/hash_calc.rs

+        Self::quick_insert_value(state, string, val)
+    }
+
+    pub fn quick_insert_value(state: &mut State, string: usize, val: u32) -> u16 {


for me, this needs an #[inline], otherwise level 2 regresses by a couple of percent. Interestingly I then see some improvements for the other compression levels too (mostly in instructions), maybe because different (better) inlining decisions are made.

brian-pane · 2025-05-28T19:20:06Z

With the #[inline] added, the results on my test system are:

Benchmark 1 (69 runs): ./blogpost-compress-baseline 1 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time          73.3ms ± 1.77ms    72.1ms … 86.9ms          2 ( 3%)        0%
  peak_rss           26.6MB ± 68.7KB    26.5MB … 26.8MB          0 ( 0%)        0%
  cpu_cycles          282M  ±  747K      280M  …  283M           3 ( 4%)        0%
  instructions        549M  ±  273       549M  …  549M           0 ( 0%)        0%
  cache_references    265K  ± 6.58K      260K  …  311K           3 ( 4%)        0%
  cache_misses        230K  ± 8.12K      195K  …  247K           6 ( 9%)        0%
  branch_misses      2.88M  ± 9.40K     2.86M  … 2.91M           1 ( 1%)        0%
Benchmark 2 (72 runs): ./target/release/examples/blogpost-compress 1 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time          69.8ms ±  568us    69.1ms … 71.5ms          4 ( 6%)        ⚡-  4.7% ±  0.6%
  peak_rss           26.6MB ± 64.0KB    26.5MB … 26.7MB          0 ( 0%)          -  0.0% ±  0.1%
  cpu_cycles          267M  ±  663K      266M  …  271M           1 ( 1%)        ⚡-  5.1% ±  0.1%
  instructions        524M  ±  294       524M  …  524M           0 ( 0%)        ⚡-  4.6% ±  0.0%
  cache_references    265K  ± 3.94K      260K  …  281K           6 ( 8%)          -  0.0% ±  0.7%
  cache_misses        230K  ± 8.40K      191K  …  241K           7 (10%)          +  0.1% ±  1.2%
  branch_misses      2.85M  ± 4.86K     2.83M  … 2.86M           1 ( 1%)        ⚡-  1.3% ±  0.1%
Benchmark 1 (42 runs): ./blogpost-compress-baseline 2 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time           120ms ± 1.06ms     119ms …  124ms          3 ( 7%)        0%
  peak_rss           24.9MB ± 57.4KB    24.8MB … 25.0MB          0 ( 0%)        0%
  cpu_cycles          486M  ± 2.99M      484M  …  504M           1 ( 2%)        0%
  instructions       1.07G  ±  283      1.07G  … 1.07G           1 ( 2%)        0%
  cache_references    269K  ± 5.36K      264K  …  291K           3 ( 7%)        0%
  cache_misses        233K  ± 7.27K      209K  …  245K           6 (14%)        0%
  branch_misses      6.18M  ± 5.05K     6.17M  … 6.19M           0 ( 0%)        0%
Benchmark 2 (42 runs): ./target/release/examples/blogpost-compress 2 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time           120ms ±  924us     119ms …  124ms          3 ( 7%)          +  0.2% ±  0.4%
  peak_rss           24.9MB ± 67.1KB    24.7MB … 25.0MB          1 ( 2%)          -  0.1% ±  0.1%
  cpu_cycles          487M  ± 1.28M      485M  …  489M           0 ( 0%)          +  0.1% ±  0.2%
  instructions       1.07G  ±  386      1.07G  … 1.07G           4 (10%)          +  0.0% ±  0.0%
  cache_references    268K  ± 4.72K      263K  …  289K           3 ( 7%)          -  0.4% ±  0.8%
  cache_misses        234K  ± 5.38K      213K  …  246K           3 ( 7%)          +  0.4% ±  1.2%
  branch_misses      6.19M  ± 7.92K     6.17M  … 6.20M           0 ( 0%)          +  0.1% ±  0.0%
Benchmark 1 (37 runs): ./blogpost-compress-baseline 3 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time           137ms ±  746us     136ms …  139ms          2 ( 5%)        0%
  peak_rss           24.7MB ± 69.8KB    24.6MB … 24.8MB          0 ( 0%)        0%
  cpu_cycles          561M  ± 1.89M      559M  …  569M           1 ( 3%)        0%
  instructions       1.40G  ±  373      1.40G  … 1.40G           1 ( 3%)        0%
  cache_references    270K  ± 5.25K      264K  …  290K           4 (11%)        0%
  cache_misses        232K  ± 8.90K      207K  …  245K           6 (16%)        0%
  branch_misses      7.06M  ± 5.46K     7.05M  … 7.07M           0 ( 0%)        0%
Benchmark 2 (37 runs): ./target/release/examples/blogpost-compress 3 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time           137ms ±  645us     136ms …  138ms          0 ( 0%)          -  0.0% ±  0.2%
  peak_rss           24.7MB ± 77.3KB    24.5MB … 24.8MB          0 ( 0%)          +  0.0% ±  0.1%
  cpu_cycles          560M  ± 1.58M      558M  …  566M           1 ( 3%)          -  0.1% ±  0.1%
  instructions       1.40G  ±  346      1.40G  … 1.40G           2 ( 5%)          +  0.0% ±  0.0%
  cache_references    273K  ± 14.5K      265K  …  340K           4 (11%)          +  1.1% ±  1.9%
  cache_misses        231K  ± 8.99K      206K  …  241K           7 (19%)          -  0.2% ±  1.8%
  branch_misses      7.04M  ± 4.09K     7.03M  … 7.05M           0 ( 0%)          -  0.4% ±  0.0%
Benchmark 1 (32 runs): ./blogpost-compress-baseline 4 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time           160ms ± 1.50ms     159ms …  165ms          3 ( 9%)        0%
  peak_rss           24.5MB ± 87.8KB    24.4MB … 24.7MB          1 ( 3%)        0%
  cpu_cycles          662M  ± 4.91M      659M  …  681M           5 (16%)        0%
  instructions       1.50G  ±  317      1.50G  … 1.50G           0 ( 0%)        0%
  cache_references    274K  ± 13.8K      265K  …  336K           5 (16%)        0%
  cache_misses        235K  ± 6.20K      206K  …  246K           3 ( 9%)        0%
  branch_misses      7.65M  ± 4.45K     7.64M  … 7.66M           1 ( 3%)        0%
Benchmark 2 (32 runs): ./target/release/examples/blogpost-compress 4 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time           160ms ± 3.38ms     158ms …  175ms          5 (16%)          +  0.4% ±  0.8%
  peak_rss           24.5MB ± 74.9KB    24.3MB … 24.7MB          1 ( 3%)          -  0.1% ±  0.2%
  cpu_cycles          663M  ± 10.4M      658M  …  712M           6 (19%)          +  0.2% ±  0.6%
  instructions       1.50G  ±  277      1.50G  … 1.50G           0 ( 0%)          +  0.0% ±  0.0%
  cache_references    277K  ± 26.4K      265K  …  398K           2 ( 6%)          +  1.4% ±  3.8%
  cache_misses        235K  ± 8.44K      204K  …  248K           7 (22%)          +  0.2% ±  1.6%
  branch_misses      7.56M  ± 22.4K     7.54M  … 7.67M           2 ( 6%)        ⚡-  1.2% ±  0.1%
Benchmark 1 (29 runs): ./blogpost-compress-baseline 5 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time           175ms ± 1.01ms     174ms …  178ms          1 ( 3%)        0%
  peak_rss           24.5MB ± 88.6KB    24.3MB … 24.7MB          1 ( 3%)        0%
  cpu_cycles          728M  ±  728K      727M  …  730M           1 ( 3%)        0%
  instructions       1.73G  ±  557      1.73G  … 1.73G           2 ( 7%)        0%
  cache_references    270K  ± 6.47K      265K  …  295K           3 (10%)        0%
  cache_misses        234K  ± 6.63K      209K  …  246K           3 (10%)        0%
  branch_misses      8.21M  ± 5.09K     8.20M  … 8.22M           0 ( 0%)        0%
Benchmark 2 (29 runs): ./target/release/examples/blogpost-compress 5 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time           176ms ±  599us     175ms …  178ms          1 ( 3%)          +  0.5% ±  0.3%
  peak_rss           24.6MB ± 58.5KB    24.4MB … 24.7MB          1 ( 3%)          +  0.1% ±  0.2%
  cpu_cycles          733M  ± 1.44M      731M  …  737M           0 ( 0%)          +  0.7% ±  0.1%
  instructions       1.73G  ±  318      1.73G  … 1.73G           2 ( 7%)          +  0.0% ±  0.0%
  cache_references    270K  ± 7.28K      264K  …  297K           3 (10%)          +  0.0% ±  1.3%
  cache_misses        233K  ± 6.86K      208K  …  240K           2 ( 7%)          -  0.2% ±  1.5%
  branch_misses      8.28M  ± 36.3K     8.23M  … 8.36M           0 ( 0%)          +  0.8% ±  0.2%
Benchmark 1 (24 runs): ./blogpost-compress-baseline 6 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time           215ms ±  810us     214ms …  218ms          1 ( 4%)        0%
  peak_rss           24.5MB ± 77.8KB    24.4MB … 24.7MB          0 ( 0%)        0%
  cpu_cycles          902M  ± 1.28M      900M  …  905M           1 ( 4%)        0%
  instructions       1.90G  ±  369      1.90G  … 1.90G           2 ( 8%)        0%
  cache_references    273K  ± 7.42K      266K  …  301K           1 ( 4%)        0%
  cache_misses        234K  ± 7.23K      211K  …  241K           2 ( 8%)        0%
  branch_misses      8.35M  ± 6.15K     8.34M  … 8.36M           1 ( 4%)        0%
Benchmark 2 (24 runs): ./target/release/examples/blogpost-compress 6 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time           217ms ± 1.05ms     216ms …  220ms          1 ( 4%)          +  0.9% ±  0.3%
  peak_rss           24.5MB ± 84.6KB    24.4MB … 24.7MB          0 ( 0%)          -  0.0% ±  0.2%
  cpu_cycles          908M  ± 1.13M      906M  …  910M           0 ( 0%)          +  0.7% ±  0.1%
  instructions       1.90G  ±  353      1.90G  … 1.90G           0 ( 0%)          +  0.0% ±  0.0%
  cache_references    271K  ± 7.60K      266K  …  293K           3 (13%)          -  0.5% ±  1.6%
  cache_misses        235K  ± 6.84K      208K  …  246K           4 (17%)          +  0.4% ±  1.8%
  branch_misses      8.45M  ± 34.4K     8.39M  … 8.51M           2 ( 8%)        💩+  1.3% ±  0.2%
Benchmark 1 (17 runs): ./blogpost-compress-baseline 7 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time           299ms ± 1.03ms     298ms …  300ms          0 ( 0%)        0%
  peak_rss           24.4MB ± 65.2KB    24.3MB … 24.5MB          0 ( 0%)        0%
  cpu_cycles         1.25G  ± 2.00M     1.25G  … 1.26G           1 ( 6%)        0%
  instructions       2.30G  ±  297      2.30G  … 2.30G           0 ( 0%)        0%
  cache_references    275K  ± 8.87K      265K  …  296K           0 ( 0%)        0%
  cache_misses        235K  ± 6.50K      216K  …  241K           2 (12%)        0%
  branch_misses      9.52M  ± 9.74K     9.51M  … 9.54M           1 ( 6%)        0%
Benchmark 2 (17 runs): ./target/release/examples/blogpost-compress 7 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time           300ms ± 1.42ms     299ms …  304ms          1 ( 6%)          +  0.3% ±  0.3%
  peak_rss           24.4MB ± 71.6KB    24.3MB … 24.5MB          0 ( 0%)          +  0.0% ±  0.2%
  cpu_cycles         1.26G  ± 3.56M     1.26G  … 1.27G           1 ( 6%)          +  0.3% ±  0.2%
  instructions       2.30G  ±  268      2.30G  … 2.30G           0 ( 0%)          +  0.0% ±  0.0%
  cache_references    275K  ± 10.6K      266K  …  309K           1 ( 6%)          +  0.1% ±  2.5%
  cache_misses        237K  ± 6.98K      212K  …  247K           2 (12%)          +  1.0% ±  2.0%
  branch_misses      9.56M  ± 12.8K     9.53M  … 9.58M           0 ( 0%)          +  0.4% ±  0.1%
Benchmark 1 (13 runs): ./blogpost-compress-baseline 8 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time           394ms ± 1.11ms     393ms …  397ms          0 ( 0%)        0%
  peak_rss           24.4MB ± 61.8KB    24.4MB … 24.6MB          1 ( 8%)        0%
  cpu_cycles         1.66G  ± 1.34M     1.66G  … 1.66G           0 ( 0%)        0%
  instructions       2.75G  ±  344      2.75G  … 2.75G           1 ( 8%)        0%
  cache_references    275K  ± 10.3K      266K  …  304K           1 ( 8%)        0%
  cache_misses        234K  ± 9.75K      217K  …  250K           0 ( 0%)        0%
  branch_misses      9.65M  ± 11.3K     9.63M  … 9.67M           0 ( 0%)        0%
Benchmark 2 (13 runs): ./target/release/examples/blogpost-compress 8 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time           396ms ± 1.74ms     394ms …  399ms          0 ( 0%)          +  0.3% ±  0.3%
  peak_rss           24.4MB ± 74.7KB    24.2MB … 24.5MB          1 ( 8%)          -  0.3% ±  0.2%
  cpu_cycles         1.66G  ± 3.41M     1.66G  … 1.67G           1 ( 8%)          +  0.3% ±  0.1%
  instructions       2.75G  ±  450      2.75G  … 2.75G           0 ( 0%)          +  0.0% ±  0.0%
  cache_references    288K  ± 39.1K      264K  …  412K           1 ( 8%)          +  4.7% ±  8.4%
  cache_misses        237K  ± 7.25K      216K  …  244K           1 ( 8%)          +  1.1% ±  3.0%
  branch_misses      9.69M  ± 8.48K     9.67M  … 9.70M           0 ( 0%)          +  0.4% ±  0.1%
Benchmark 1 (12 runs): ./blogpost-compress-baseline 9 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time           421ms ± 3.65ms     418ms …  430ms          1 ( 8%)        0%
  peak_rss           24.4MB ± 75.3KB    24.2MB … 24.5MB          0 ( 0%)        0%
  cpu_cycles         1.77G  ± 9.52M     1.77G  … 1.79G           2 (17%)        0%
  instructions       3.38G  ±  225      3.38G  … 3.38G           3 (25%)        0%
  cache_references    278K  ± 10.2K      267K  …  303K           0 ( 0%)        0%
  cache_misses        239K  ± 4.79K      231K  …  248K           0 ( 0%)        0%
  branch_misses      15.5M  ± 36.9K     15.5M  … 15.6M           0 ( 0%)        0%
Benchmark 2 (12 runs): ./target/release/examples/blogpost-compress 9 rs silesia-small.tar
  measurement          mean ± σ            min … max           outliers         delta
  wall_time           421ms ± 1.42ms     420ms …  424ms          0 ( 0%)          -  0.0% ±  0.6%
  peak_rss           24.4MB ± 81.1KB    24.2MB … 24.5MB          4 (33%)          +  0.2% ±  0.3%
  cpu_cycles         1.77G  ± 1.75M     1.77G  … 1.78G           2 (17%)          +  0.1% ±  0.3%
  instructions       3.38G  ±  269      3.38G  … 3.38G           0 ( 0%)          +  0.0% ±  0.0%
  cache_references    277K  ± 13.9K      268K  …  318K           1 ( 8%)          -  0.7% ±  3.7%
  cache_misses        235K  ± 6.98K      221K  …  244K           2 (17%)          -  1.6% ±  2.1%
  branch_misses      15.8M  ± 27.9K     15.8M  … 15.9M           0 ( 0%)        💩+  1.9% ±  0.2%

folkertdev

great work, thanks!

folkertdev reviewed May 28, 2025

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Optimize out some read operations from the quick deflate algorithm

c194953

brian-pane force-pushed the reuse-read branch from c89c048 to c194953 Compare May 28, 2025 18:46

folkertdev approved these changes May 28, 2025

View reviewed changes

folkertdev merged commit d154bf0 into trifectatechfoundation:main May 28, 2025
24 checks passed

brian-pane deleted the reuse-read branch May 28, 2025 21:29

BrewTestBot mentioned this pull request Jun 6, 2025

zlib-rs 0.5.1 Homebrew/homebrew-core#225936

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Optimize out some read operations from the quick deflate algorithm #374

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