buffer: improve byteLength performance

[anonrig]

This improves the performance for non one-byte strings.

Benchmark CI: https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/1705/

[codecov]

Codecov Report

Attention: Patch coverage is 41.66667% with 7 lines in your changes missing coverage. Please review.

Project coverage is 90.19%. Comparing base (e0cf8ae) to head (5bf5393).
Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
src/node_buffer.cc	41.66%	5 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #58048      +/-   ##
==========================================
+ Coverage   90.18%   90.19%   +0.01%     
==========================================
  Files         630      630              
  Lines      186393   186400       +7     
  Branches    36595    36601       +6     
==========================================
+ Hits       168103   168131      +28     
+ Misses      11090    11086       -4     
+ Partials     7200     7183      -17     

Files with missing lines	Coverage Δ
src/node_external_reference.h	100.00% <ø> (ø)
src/node_buffer.cc	67.63% <41.66%> (+0.12%)	⬆️

... and 21 files with indirect coverage changes

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[ronag]

Looks like some pretty bad performance regressions.

[anonrig]

One more shot: https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/1705/

waiting for bench resultd

[anonrig]

The results are in

15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=1 encoding='base64' type='four_bytes'                                                                      1.84 %       ±3.25%  ±4.32%  ±5.62%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=1 encoding='base64' type='latin1'                                                                         -1.79 %       ±3.18%  ±4.24%  ±5.51%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=1 encoding='base64' type='one_byte'                                                                       -0.58 %       ±2.71%  ±3.61%  ±4.69%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=1 encoding='base64' type='three_bytes'                                                                    -1.06 %       ±3.23%  ±4.30%  ±5.59%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=1 encoding='base64' type='two_bytes'                                                                       0.75 %       ±3.07%  ±4.09%  ±5.32%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=1 encoding='utf8' type='four_bytes'                                                                       -0.60 %       ±0.88%  ±1.18%  ±1.54%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=1 encoding='utf8' type='latin1'                                                                            0.83 %       ±1.00%  ±1.33%  ±1.73%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=1 encoding='utf8' type='one_byte'                                                                   *     -2.74 %       ±2.07%  ±2.77%  ±3.62%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=1 encoding='utf8' type='three_bytes'                                                              ***     -2.52 %       ±0.89%  ±1.18%  ±1.54%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=1 encoding='utf8' type='two_bytes'                                                                  *     -1.88 %       ±1.52%  ±2.02%  ±2.63%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=16 encoding='base64' type='four_bytes'                                                                     0.23 %       ±2.36%  ±3.14%  ±4.09%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=16 encoding='base64' type='latin1'                                                                         0.84 %       ±2.40%  ±3.19%  ±4.15%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=16 encoding='base64' type='one_byte'                                                                      -2.16 %       ±2.81%  ±3.73%  ±4.86%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=16 encoding='base64' type='three_bytes'                                                             *     -2.65 %       ±2.49%  ±3.32%  ±4.32%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=16 encoding='base64' type='two_bytes'                                                                     -2.01 %       ±2.63%  ±3.49%  ±4.55%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=16 encoding='utf8' type='four_bytes'                                                                       0.01 %       ±0.12%  ±0.16%  ±0.20%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=16 encoding='utf8' type='latin1'                                                                    *      0.12 %       ±0.11%  ±0.15%  ±0.19%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=16 encoding='utf8' type='one_byte'                                                                ***      3.05 %       ±0.80%  ±1.07%  ±1.39%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=16 encoding='utf8' type='three_bytes'                                                               *      0.29 %       ±0.27%  ±0.36%  ±0.47%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=16 encoding='utf8' type='two_bytes'                                                               ***      0.91 %       ±0.35%  ±0.47%  ±0.61%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=2 encoding='base64' type='four_bytes'                                                                      0.30 %       ±2.71%  ±3.61%  ±4.70%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=2 encoding='base64' type='latin1'                                                                         -0.26 %       ±2.60%  ±3.46%  ±4.51%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=2 encoding='base64' type='one_byte'                                                                       -1.51 %       ±3.12%  ±4.16%  ±5.41%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=2 encoding='base64' type='three_bytes'                                                                    -2.08 %       ±2.33%  ±3.10%  ±4.04%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=2 encoding='base64' type='two_bytes'                                                                      -0.71 %       ±2.41%  ±3.20%  ±4.17%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=2 encoding='utf8' type='four_bytes'                                                                 *     -0.89 %       ±0.70%  ±0.94%  ±1.22%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=2 encoding='utf8' type='latin1'                                                                   ***      2.30 %       ±0.40%  ±0.53%  ±0.69%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=2 encoding='utf8' type='one_byte'                                                                 ***     -5.70 %       ±2.12%  ±2.83%  ±3.70%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=2 encoding='utf8' type='three_bytes'                                                              ***      7.95 %       ±1.76%  ±2.34%  ±3.06%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=2 encoding='utf8' type='two_bytes'                                                                ***      3.18 %       ±1.50%  ±1.99%  ±2.60%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=256 encoding='base64' type='four_bytes'                                                                   -0.37 %       ±2.43%  ±3.24%  ±4.23%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=256 encoding='base64' type='latin1'                                                                       -1.11 %       ±2.77%  ±3.68%  ±4.79%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=256 encoding='base64' type='one_byte'                                                                      1.55 %       ±2.98%  ±3.96%  ±5.16%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=256 encoding='base64' type='three_bytes'                                                                   1.09 %       ±2.57%  ±3.42%  ±4.45%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=256 encoding='base64' type='two_bytes'                                                                    -0.58 %       ±2.20%  ±2.93%  ±3.81%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=256 encoding='utf8' type='four_bytes'                                                             ***     -0.01 %       ±0.01%  ±0.01%  ±0.01%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=256 encoding='utf8' type='latin1'                                                                 ***     -0.20 %       ±0.03%  ±0.04%  ±0.06%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=256 encoding='utf8' type='one_byte'                                                                       -0.02 %       ±0.20%  ±0.27%  ±0.35%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=256 encoding='utf8' type='three_bytes'                                                                     0.02 %       ±0.03%  ±0.04%  ±0.05%
15:35:23 buffers/buffer-bytelength-string.js n=4000000 repeat=256 encoding='utf8' type='two_bytes'                                                              ***     -0.78 %       ±0.09%  ±0.12%  ±0.16%

[jasnell]

From those results it appears like mostly a wash in terms of perf improvement but the change still looks worthwhile to me.

[anonrig]

cc @ronag

[mcollina]

lgtm

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/66498/