(Improvements) Rune operations optimization #1252

pl752 · 2025-12-29T07:07:41Z

Decided to split up my previous pull request (#1247) to multiple PRs due to it having set of changes too broad in my opinion. Ran tests as usual for fb3 server and embedded. Updated to current master branch state.

TLDR: Small set of optimizations, improving speed and alloc volumes of string methods tenfold (up to 3x if including I/O and real db engine for select queries containing char100 field in my case) and also including ability to better utilize modern processors SIMD instructions for BMP-only (single char per rune) strings.

Synthetic (serverless, no I/O) benchmarks

Implemented rune ops:

// * Summary *

BenchmarkDotNet v0.15.8, Windows 10 (10.0.19044.6691/21H2/November2021Update)
AMD Ryzen 7 5800H with Radeon Graphics 3.20GHz, 1 CPU, 16 logical and 8 physical cores
.NET SDK 10.0.101
  [Host]     : .NET 8.0.22 (8.0.22, 8.0.2225.52707), X64 RyuJIT x86-64-v3
  Job-JMDAGQ : .NET 10.0.1 (10.0.1, 10.0.125.57005), X64 RyuJIT x86-64-v3
  Job-OOTPKI : .NET 8.0.22 (8.0.22, 8.0.2225.52707), X64 RyuJIT x86-64-v3


| Method                                       | Job        | Toolchain | Kind                 | RuneLength | MaxRuneCount | Mean        | Error     | StdDev    | Gen0   | Allocated |
|--------------------------------------------- |----------- |---------- |--------------------- |----------- |------------- |------------:|----------:|----------:|-------:|----------:|
| 'old truncate via EnumerateRunesToChars'     | Job-JMDAGQ | .NET 10.0 | Ascii                | 128        | 512          |  2,490.0 ns |  39.22 ns |  36.69 ns | 1.0414 |    8712 B |
| 'new TruncateStringToRuneCount().ToString()' | Job-JMDAGQ | .NET 10.0 | Ascii                | 128        | 512          |    110.8 ns |   2.15 ns |   1.91 ns | 0.0334 |     280 B |
| 'old truncate via EnumerateRunesToChars'     | Job-OOTPKI | .NET 8.0  | Ascii                | 128        | 512          |  3,002.9 ns |  54.82 ns |  51.27 ns | 1.0414 |    8712 B |
| 'new TruncateStringToRuneCount().ToString()' | Job-OOTPKI | .NET 8.0  | Ascii                | 128        | 512          |    108.2 ns |   1.94 ns |   1.81 ns | 0.0334 |     280 B |
| 'old truncate via EnumerateRunesToChars'     | Job-JMDAGQ | .NET 10.0 | Ascii                | 1024       | 512          |  9,842.2 ns | 196.62 ns | 201.91 ns | 4.0588 |   34056 B |
| 'new TruncateStringToRuneCount().ToString()' | Job-JMDAGQ | .NET 10.0 | Ascii                | 1024       | 512          |    376.1 ns |   4.77 ns |   4.46 ns | 0.1249 |    1048 B |
| 'old truncate via EnumerateRunesToChars'     | Job-OOTPKI | .NET 8.0  | Ascii                | 1024       | 512          | 11,843.6 ns | 178.52 ns | 166.99 ns | 4.0588 |   34056 B |
| 'new TruncateStringToRuneCount().ToString()' | Job-OOTPKI | .NET 8.0  | Ascii                | 1024       | 512          |    423.3 ns |   7.58 ns |   6.72 ns | 0.1249 |    1048 B |
| 'old truncate via EnumerateRunesToChars'     | Job-JMDAGQ | .NET 10.0 | Mixed(...)gates [21] | 128        | 512          |  2,749.5 ns |  53.15 ns |  49.72 ns | 1.0490 |    8776 B |
| 'new TruncateStringToRuneCount().ToString()' | Job-JMDAGQ | .NET 10.0 | Mixed(...)gates [21] | 128        | 512          |    133.1 ns |   2.38 ns |   2.11 ns | 0.0410 |     344 B |
| 'old truncate via EnumerateRunesToChars'     | Job-OOTPKI | .NET 8.0  | Mixed(...)gates [21] | 128        | 512          |  3,315.5 ns |  61.21 ns |  57.26 ns | 1.0490 |    8776 B |
| 'new TruncateStringToRuneCount().ToString()' | Job-OOTPKI | .NET 8.0  | Mixed(...)gates [21] | 128        | 512          |    126.6 ns |   1.03 ns |   0.91 ns | 0.0410 |     344 B |
| 'old truncate via EnumerateRunesToChars'     | Job-JMDAGQ | .NET 10.0 | Mixed(...)gates [21] | 1024       | 512          | 10,957.8 ns | 157.33 ns | 139.47 ns | 4.0894 |   34312 B |
| 'new TruncateStringToRuneCount().ToString()' | Job-JMDAGQ | .NET 10.0 | Mixed(...)gates [21] | 1024       | 512          |    453.9 ns |   8.40 ns |   7.86 ns | 0.1554 |    1304 B |
| 'old truncate via EnumerateRunesToChars'     | Job-OOTPKI | .NET 8.0  | Mixed(...)gates [21] | 1024       | 512          | 12,647.8 ns | 113.42 ns | 100.54 ns | 4.0894 |   34312 B |
| 'new TruncateStringToRuneCount().ToString()' | Job-OOTPKI | .NET 8.0  | Mixed(...)gates [21] | 1024       | 512          |    449.2 ns |   5.65 ns |   5.01 ns | 0.1554 |    1304 B |
| 'old truncate via EnumerateRunesToChars'     | Job-JMDAGQ | .NET 10.0 | MostlySurrogates     | 128        | 512          |  3,225.2 ns |  28.44 ns |  25.21 ns | 1.0681 |    8936 B |
| 'new TruncateStringToRuneCount().ToString()' | Job-JMDAGQ | .NET 10.0 | MostlySurrogates     | 128        | 512          |    165.1 ns |   3.34 ns |   5.67 ns | 0.0601 |     504 B |
| 'old truncate via EnumerateRunesToChars'     | Job-OOTPKI | .NET 8.0  | MostlySurrogates     | 128        | 512          |  3,867.0 ns |  40.20 ns |  37.61 ns | 1.0681 |    8936 B |
| 'new TruncateStringToRuneCount().ToString()' | Job-OOTPKI | .NET 8.0  | MostlySurrogates     | 128        | 512          |    161.0 ns |   3.25 ns |   7.84 ns | 0.0601 |     504 B |
| 'old truncate via EnumerateRunesToChars'     | Job-JMDAGQ | .NET 10.0 | MostlySurrogates     | 1024       | 512          | 13,368.1 ns | 239.05 ns | 211.91 ns | 4.1656 |   34952 B |
| 'new TruncateStringToRuneCount().ToString()' | Job-JMDAGQ | .NET 10.0 | MostlySurrogates     | 1024       | 512          |    584.4 ns |  10.15 ns |   9.00 ns | 0.2317 |    1944 B |
| 'old truncate via EnumerateRunesToChars'     | Job-OOTPKI | .NET 8.0  | MostlySurrogates     | 1024       | 512          | 15,874.9 ns | 213.65 ns | 199.85 ns | 4.1656 |   34952 B |
| 'new TruncateStringToRuneCount().ToString()' | Job-OOTPKI | .NET 8.0  | MostlySurrogates     | 1024       | 512          |    592.7 ns |  11.31 ns |  10.58 ns | 0.2317 |    1944 B |
  
| Method                                   | Job        | Toolchain | Kind                 | RuneLength | Mean         | Error        | StdDev       | Median       | Gen0    | Allocated |
|----------------------------------------- |----------- |---------- |--------------------- |----------- |-------------:|-------------:|-------------:|-------------:|--------:|----------:|
| 'old Count() over EnumerateRunesToChars' | Job-JMDAGQ | .NET 10.0 | Ascii                | 128        |    619.63 ns |    11.920 ns |    11.707 ns |    620.95 ns |  0.5035 |    4216 B |
| 'new CountRunes(span)'                   | Job-JMDAGQ | .NET 10.0 | Ascii                | 128        |     64.97 ns |     0.332 ns |     0.294 ns |     64.97 ns |       - |         - |
| 'old Count() over EnumerateRunesToChars' | Job-OOTPKI | .NET 8.0  | Ascii                | 128        |    754.45 ns |    14.865 ns |    31.678 ns |    745.93 ns |  0.5035 |    4216 B |
| 'new CountRunes(span)'                   | Job-OOTPKI | .NET 8.0  | Ascii                | 128        |     66.31 ns |     0.209 ns |     0.196 ns |     66.30 ns |       - |         - |
| 'old Count() over EnumerateRunesToChars' | Job-JMDAGQ | .NET 10.0 | Ascii                | 8192       | 35,601.63 ns |   693.533 ns | 1,886.808 ns | 34,675.31 ns | 31.3110 |  262264 B |
| 'new CountRunes(span)'                   | Job-JMDAGQ | .NET 10.0 | Ascii                | 8192       |  3,909.67 ns |    23.210 ns |    21.711 ns |  3,901.30 ns |       - |         - |
| 'old Count() over EnumerateRunesToChars' | Job-OOTPKI | .NET 8.0  | Ascii                | 8192       | 46,619.68 ns |   920.902 ns | 1,752.112 ns | 46,408.94 ns | 31.3110 |  262264 B |
| 'new CountRunes(span)'                   | Job-OOTPKI | .NET 8.0  | Ascii                | 8192       |  3,924.67 ns |    15.360 ns |    14.368 ns |  3,921.15 ns |       - |         - |
| 'old Count() over EnumerateRunesToChars' | Job-JMDAGQ | .NET 10.0 | Mixed(...)gates [21] | 128        |    649.58 ns |    11.920 ns |    11.150 ns |    651.50 ns |  0.5035 |    4216 B |
| 'new CountRunes(span)'                   | Job-JMDAGQ | .NET 10.0 | Mixed(...)gates [21] | 128        |     74.12 ns |     1.125 ns |     0.939 ns |     74.00 ns |       - |         - |
| 'old Count() over EnumerateRunesToChars' | Job-OOTPKI | .NET 8.0  | Mixed(...)gates [21] | 128        |    745.95 ns |    14.848 ns |    14.583 ns |    749.10 ns |  0.5035 |    4216 B |
| 'new CountRunes(span)'                   | Job-OOTPKI | .NET 8.0  | Mixed(...)gates [21] | 128        |     81.77 ns |     0.479 ns |     0.374 ns |     81.83 ns |       - |         - |
| 'old Count() over EnumerateRunesToChars' | Job-JMDAGQ | .NET 10.0 | Mixed(...)gates [21] | 8192       | 38,241.41 ns |   592.292 ns |   462.423 ns | 38,313.08 ns | 31.3110 |  262264 B |
| 'new CountRunes(span)'                   | Job-JMDAGQ | .NET 10.0 | Mixed(...)gates [21] | 8192       |  4,373.03 ns |    11.984 ns |    10.623 ns |  4,372.00 ns |       - |         - |
| 'old Count() over EnumerateRunesToChars' | Job-OOTPKI | .NET 8.0  | Mixed(...)gates [21] | 8192       | 45,407.27 ns |   876.842 ns | 1,140.142 ns | 45,305.08 ns | 31.3110 |  262264 B |
| 'new CountRunes(span)'                   | Job-OOTPKI | .NET 8.0  | Mixed(...)gates [21] | 8192       |  4,841.84 ns |    13.875 ns |    12.300 ns |  4,844.33 ns |       - |         - |
| 'old Count() over EnumerateRunesToChars' | Job-JMDAGQ | .NET 10.0 | MostlySurrogates     | 128        |    715.61 ns |    13.934 ns |    12.352 ns |    718.27 ns |  0.5035 |    4216 B |
| 'new CountRunes(span)'                   | Job-JMDAGQ | .NET 10.0 | MostlySurrogates     | 128        |     92.80 ns |     0.554 ns |     0.492 ns |     92.63 ns |       - |         - |
| 'old Count() over EnumerateRunesToChars' | Job-OOTPKI | .NET 8.0  | MostlySurrogates     | 128        |    814.53 ns |    16.191 ns |    31.579 ns |    796.44 ns |  0.5035 |    4216 B |
| 'new CountRunes(span)'                   | Job-OOTPKI | .NET 8.0  | MostlySurrogates     | 128        |     97.37 ns |     0.291 ns |     0.258 ns |     97.33 ns |       - |         - |
| 'old Count() over EnumerateRunesToChars' | Job-JMDAGQ | .NET 10.0 | MostlySurrogates     | 8192       | 43,324.08 ns |   835.526 ns |   781.551 ns | 43,488.72 ns | 31.3110 |  262264 B |
| 'new CountRunes(span)'                   | Job-JMDAGQ | .NET 10.0 | MostlySurrogates     | 8192       |  5,585.16 ns |    25.642 ns |    21.412 ns |  5,584.12 ns |       - |         - |
| 'old Count() over EnumerateRunesToChars' | Job-OOTPKI | .NET 8.0  | MostlySurrogates     | 8192       | 50,161.87 ns | 1,000.371 ns | 1,466.331 ns | 50,378.08 ns | 31.3110 |  262264 B |
| 'new CountRunes(span)'                   | Job-OOTPKI | .NET 8.0  | MostlySurrogates     | 8192       |  5,831.10 ns |    30.611 ns |    27.135 ns |  5,827.66 ns |       - |         - |

Added SIMD search and early bailout:

Added SIMD search:
| Method                                        | Job        | Toolchain | Kind                 | RuneLength | MaxRuneCount | Mean      | Error     | StdDev    | Median    | Ratio | RatioSD | Gen0   | Allocated | Alloc Ratio |
|---------------------------------------------- |----------- |---------- |--------------------- |----------- |------------- |----------:|----------:|----------:|----------:|------:|--------:|-------:|----------:|------------:|
| 'prev TruncateStringToRuneCount().ToString()' | Job-JMDAGQ | .NET 10.0 | Ascii                | 128        | 512          | 117.83 ns |  3.247 ns |  9.472 ns | 118.01 ns |  1.01 |    0.11 | 0.0334 |     280 B |        1.00 |
| 'new TruncateStringToRuneCount().ToString()'  | Job-JMDAGQ | .NET 10.0 | Ascii                | 128        | 512          |  20.53 ns |  1.192 ns |  3.458 ns |  21.20 ns |  0.18 |    0.03 | 0.0335 |     280 B |        1.00 |
|                                               |            |           |                      |            |              |           |           |           |           |       |         |        |           |             |
| 'prev TruncateStringToRuneCount().ToString()' | Job-OOTPKI | .NET 8.0  | Ascii                | 128        | 512          | 113.01 ns |  2.309 ns |  5.836 ns | 112.96 ns |  1.00 |    0.07 | 0.0334 |     280 B |        1.00 |
| 'new TruncateStringToRuneCount().ToString()'  | Job-OOTPKI | .NET 8.0  | Ascii                | 128        | 512          |  17.22 ns |  0.272 ns |  0.302 ns |  17.14 ns |  0.15 |    0.01 | 0.0335 |     280 B |        1.00 |
|                                               |            |           |                      |            |              |           |           |           |           |       |         |        |           |             |
| 'prev TruncateStringToRuneCount().ToString()' | Job-JMDAGQ | .NET 10.0 | Ascii                | 1024       | 512          | 356.61 ns |  4.256 ns |  3.772 ns | 356.42 ns |  1.00 |    0.01 | 0.1249 |    1048 B |        1.00 |
| 'new TruncateStringToRuneCount().ToString()'  | Job-JMDAGQ | .NET 10.0 | Ascii                | 1024       | 512          |  58.19 ns |  1.418 ns |  4.024 ns |  57.35 ns |  0.16 |    0.01 | 0.1253 |    1048 B |        1.00 |
|                                               |            |           |                      |            |              |           |           |           |           |       |         |        |           |             |
| 'prev TruncateStringToRuneCount().ToString()' | Job-OOTPKI | .NET 8.0  | Ascii                | 1024       | 512          | 447.18 ns |  8.996 ns | 23.540 ns | 454.22 ns |  1.00 |    0.08 | 0.1249 |    1048 B |        1.00 |
| 'new TruncateStringToRuneCount().ToString()'  | Job-OOTPKI | .NET 8.0  | Ascii                | 1024       | 512          |  79.19 ns |  5.037 ns | 14.853 ns |  77.34 ns |  0.18 |    0.03 | 0.1253 |    1048 B |        1.00 |
|                                               |            |           |                      |            |              |           |           |           |           |       |         |        |           |             |
| 'prev TruncateStringToRuneCount().ToString()' | Job-JMDAGQ | .NET 10.0 | Mixed(...)gates [21] | 128        | 512          | 128.13 ns |  3.666 ns | 10.808 ns | 126.82 ns |  1.01 |    0.12 | 0.0410 |     344 B |        1.00 |
| 'new TruncateStringToRuneCount().ToString()'  | Job-JMDAGQ | .NET 10.0 | Mixed(...)gates [21] | 128        | 512          |  16.93 ns |  0.387 ns |  0.791 ns |  16.80 ns |  0.13 |    0.01 | 0.0411 |     344 B |        1.00 |
|                                               |            |           |                      |            |              |           |           |           |           |       |         |        |           |             |
| 'prev TruncateStringToRuneCount().ToString()' | Job-OOTPKI | .NET 8.0  | Mixed(...)gates [21] | 128        | 512          | 121.79 ns |  2.492 ns |  5.523 ns | 120.67 ns |  1.00 |    0.06 | 0.0410 |     344 B |        1.00 |
| 'new TruncateStringToRuneCount().ToString()'  | Job-OOTPKI | .NET 8.0  | Mixed(...)gates [21] | 128        | 512          |  18.89 ns |  0.391 ns |  0.858 ns |  18.66 ns |  0.16 |    0.01 | 0.0411 |     344 B |        1.00 |
|                                               |            |           |                      |            |              |           |           |           |           |       |         |        |           |             |
| 'prev TruncateStringToRuneCount().ToString()' | Job-JMDAGQ | .NET 10.0 | Mixed(...)gates [21] | 1024       | 512          | 436.43 ns |  8.777 ns | 10.449 ns | 439.27 ns |  1.00 |    0.03 | 0.1554 |    1304 B |        1.00 |
| 'new TruncateStringToRuneCount().ToString()'  | Job-JMDAGQ | .NET 10.0 | Mixed(...)gates [21] | 1024       | 512          | 376.56 ns |  7.524 ns | 14.675 ns | 374.07 ns |  0.86 |    0.04 | 0.1554 |    1304 B |        1.00 |
|                                               |            |           |                      |            |              |           |           |           |           |       |         |        |           |             |
| 'prev TruncateStringToRuneCount().ToString()' | Job-OOTPKI | .NET 8.0  | Mixed(...)gates [21] | 1024       | 512          | 422.26 ns |  5.899 ns |  5.229 ns | 423.12 ns |  1.00 |    0.02 | 0.1554 |    1304 B |        1.00 |
| 'new TruncateStringToRuneCount().ToString()'  | Job-OOTPKI | .NET 8.0  | Mixed(...)gates [21] | 1024       | 512          | 393.42 ns |  5.567 ns |  4.649 ns | 392.34 ns |  0.93 |    0.02 | 0.1554 |    1304 B |        1.00 |
|                                               |            |           |                      |            |              |           |           |           |           |       |         |        |           |             |
| 'prev TruncateStringToRuneCount().ToString()' | Job-JMDAGQ | .NET 10.0 | MostlySurrogates     | 128        | 512          | 150.52 ns |  2.176 ns |  1.817 ns | 150.22 ns |  1.00 |    0.02 | 0.0601 |     504 B |        1.00 |
| 'new TruncateStringToRuneCount().ToString()'  | Job-JMDAGQ | .NET 10.0 | MostlySurrogates     | 128        | 512          |  21.68 ns |  0.482 ns |  1.296 ns |  20.99 ns |  0.14 |    0.01 | 0.0602 |     504 B |        1.00 |
|                                               |            |           |                      |            |              |           |           |           |           |       |         |        |           |             |
| 'prev TruncateStringToRuneCount().ToString()' | Job-OOTPKI | .NET 8.0  | MostlySurrogates     | 128        | 512          | 154.18 ns |  3.114 ns |  6.361 ns | 155.56 ns |  1.00 |    0.06 | 0.0601 |     504 B |        1.00 |
| 'new TruncateStringToRuneCount().ToString()'  | Job-OOTPKI | .NET 8.0  | MostlySurrogates     | 128        | 512          |  23.86 ns |  0.502 ns |  1.390 ns |  23.22 ns |  0.16 |    0.01 | 0.0602 |     504 B |        1.00 |
|                                               |            |           |                      |            |              |           |           |           |           |       |         |        |           |             |
| 'prev TruncateStringToRuneCount().ToString()' | Job-JMDAGQ | .NET 10.0 | MostlySurrogates     | 1024       | 512          | 556.12 ns | 10.914 ns | 11.208 ns | 556.83 ns |  1.00 |    0.03 | 0.2317 |    1944 B |        1.00 |
| 'new TruncateStringToRuneCount().ToString()'  | Job-JMDAGQ | .NET 10.0 | MostlySurrogates     | 1024       | 512          | 492.66 ns |  9.859 ns |  9.222 ns | 490.17 ns |  0.89 |    0.02 | 0.2317 |    1944 B |        1.00 |
|                                               |            |           |                      |            |              |           |           |           |           |       |         |        |           |             |
| 'prev TruncateStringToRuneCount().ToString()' | Job-OOTPKI | .NET 8.0  | MostlySurrogates     | 1024       | 512          | 545.49 ns |  8.397 ns |  7.444 ns | 544.45 ns |  1.00 |    0.02 | 0.2317 |    1944 B |        1.00 |
| 'new TruncateStringToRuneCount().ToString()'  | Job-OOTPKI | .NET 8.0  | MostlySurrogates     | 1024       | 512          | 557.46 ns | 10.655 ns | 10.464 ns | 556.98 ns |  1.02 |    0.02 | 0.2317 |    1944 B |        1.00 |

| Method                  | Job        | Toolchain | Kind                 | RuneLength | Mean         | Error      | StdDev     | Ratio | RatioSD | Allocated | Alloc Ratio |
|------------------------ |----------- |---------- |--------------------- |----------- |-------------:|-----------:|-----------:|------:|--------:|----------:|------------:|
| 'prev CountRunes(span)' | Job-JMDAGQ | .NET 10.0 | Ascii                | 128        |    70.216 ns |  1.3830 ns |  2.3484 ns |  1.00 |    0.05 |         - |          NA |
| 'new CountRunes(span)'  | Job-JMDAGQ | .NET 10.0 | Ascii                | 128        |     4.904 ns |  0.0343 ns |  0.0321 ns |  0.07 |    0.00 |         - |          NA |
|                         |            |           |                      |            |              |            |            |       |         |           |             |
| 'prev CountRunes(span)' | Job-OOTPKI | .NET 8.0  | Ascii                | 128        |    68.014 ns |  1.3878 ns |  1.4849 ns |  1.00 |    0.03 |         - |          NA |
| 'new CountRunes(span)'  | Job-OOTPKI | .NET 8.0  | Ascii                | 128        |     6.129 ns |  0.0646 ns |  0.0605 ns |  0.09 |    0.00 |         - |          NA |
|                         |            |           |                      |            |              |            |            |       |         |           |             |
| 'prev CountRunes(span)' | Job-JMDAGQ | .NET 10.0 | Ascii                | 8192       | 3,884.546 ns | 31.2551 ns | 29.2360 ns |  1.00 |    0.01 |         - |          NA |
| 'new CountRunes(span)'  | Job-JMDAGQ | .NET 10.0 | Ascii                | 8192       |   254.202 ns |  3.0534 ns |  2.5497 ns |  0.07 |    0.00 |         - |          NA |
|                         |            |           |                      |            |              |            |            |       |         |           |             |
| 'prev CountRunes(span)' | Job-OOTPKI | .NET 8.0  | Ascii                | 8192       | 4,064.459 ns | 42.3702 ns | 37.5601 ns |  1.00 |    0.01 |         - |          NA |
| 'new CountRunes(span)'  | Job-OOTPKI | .NET 8.0  | Ascii                | 8192       |   254.313 ns |  4.4622 ns |  4.1739 ns |  0.06 |    0.00 |         - |          NA |
|                         |            |           |                      |            |              |            |            |       |         |           |             |
| 'prev CountRunes(span)' | Job-JMDAGQ | .NET 10.0 | Mixed(...)gates [21] | 128        |    74.100 ns |  0.8221 ns |  0.7690 ns |  1.00 |    0.01 |         - |          NA |
| 'new CountRunes(span)'  | Job-JMDAGQ | .NET 10.0 | Mixed(...)gates [21] | 128        |    77.034 ns |  1.5091 ns |  1.8533 ns |  1.04 |    0.03 |         - |          NA |
|                         |            |           |                      |            |              |            |            |       |         |           |             |
| 'prev CountRunes(span)' | Job-OOTPKI | .NET 8.0  | Mixed(...)gates [21] | 128        |    85.025 ns |  1.7147 ns |  2.4037 ns |  1.00 |    0.04 |         - |          NA |
| 'new CountRunes(span)'  | Job-OOTPKI | .NET 8.0  | Mixed(...)gates [21] | 128        |    85.963 ns |  0.7137 ns |  0.5960 ns |  1.01 |    0.03 |         - |          NA |
|                         |            |           |                      |            |              |            |            |       |         |           |             |
| 'prev CountRunes(span)' | Job-JMDAGQ | .NET 10.0 | Mixed(...)gates [21] | 8192       | 4,396.650 ns | 58.2950 ns | 54.5292 ns |  1.00 |    0.02 |         - |          NA |
| 'new CountRunes(span)'  | Job-JMDAGQ | .NET 10.0 | Mixed(...)gates [21] | 8192       | 4,434.144 ns | 22.8985 ns | 21.4193 ns |  1.01 |    0.01 |         - |          NA |
|                         |            |           |                      |            |              |            |            |       |         |           |             |
| 'prev CountRunes(span)' | Job-OOTPKI | .NET 8.0  | Mixed(...)gates [21] | 8192       | 4,904.013 ns | 41.1963 ns | 34.4008 ns |  1.00 |    0.01 |         - |          NA |
| 'new CountRunes(span)'  | Job-OOTPKI | .NET 8.0  | Mixed(...)gates [21] | 8192       | 4,822.738 ns | 31.6198 ns | 29.5771 ns |  0.98 |    0.01 |         - |          NA |
|                         |            |           |                      |            |              |            |            |       |         |           |             |
| 'prev CountRunes(span)' | Job-JMDAGQ | .NET 10.0 | MostlySurrogates     | 128        |    94.261 ns |  0.9110 ns |  0.7607 ns |  1.00 |    0.01 |         - |          NA |
| 'new CountRunes(span)'  | Job-JMDAGQ | .NET 10.0 | MostlySurrogates     | 128        |    99.823 ns |  1.4972 ns |  1.4005 ns |  1.06 |    0.02 |         - |          NA |
|                         |            |           |                      |            |              |            |            |       |         |           |             |
| 'prev CountRunes(span)' | Job-OOTPKI | .NET 8.0  | MostlySurrogates     | 128        |    96.153 ns |  0.3468 ns |  0.3074 ns |  1.00 |    0.00 |         - |          NA |
| 'new CountRunes(span)'  | Job-OOTPKI | .NET 8.0  | MostlySurrogates     | 128        |   101.584 ns |  1.0409 ns |  0.8692 ns |  1.06 |    0.01 |         - |          NA |
|                         |            |           |                      |            |              |            |            |       |         |           |             |
| 'prev CountRunes(span)' | Job-JMDAGQ | .NET 10.0 | MostlySurrogates     | 8192       | 5,546.374 ns | 25.6919 ns | 21.4539 ns |  1.00 |    0.01 |         - |          NA |
| 'new CountRunes(span)'  | Job-JMDAGQ | .NET 10.0 | MostlySurrogates     | 8192       | 5,574.675 ns | 79.9365 ns | 70.8616 ns |  1.01 |    0.01 |         - |          NA |
|                         |            |           |                      |            |              |            |            |       |         |           |             |
| 'prev CountRunes(span)' | Job-OOTPKI | .NET 8.0  | MostlySurrogates     | 8192       | 5,686.914 ns | 37.1821 ns | 31.0488 ns |  1.00 |    0.01 |         - |          NA |
| 'new CountRunes(span)'  | Job-OOTPKI | .NET 8.0  | MostlySurrogates     | 8192       | 5,720.962 ns | 76.7373 ns | 71.7802 ns |  1.01 |    0.01 |         - |          NA |

Synthetic benchmarks demonstrate order of magnitude (or two in case of BMP-only and AVX512 in theory) improvements for methods themselves, also count and span truncation itself are alloc-free now.

Practical benchmarks (3 int and 1 char100 columns, real I/O with fb3 server on localhost and nvme)

Master:

| Method                              | Rows   | Mean         | Error      | StdDev      | Median       | Gen0        | Gen1        | Allocated     |
|------------------------------------ |------- |-------------:|-----------:|------------:|-------------:|------------:|------------:|--------------:|
| SelectAndMap_Main_ReusedBufferAsync | 10     |     1.796 ms |  0.0649 ms |   0.1904 ms |     1.784 ms |           - |           - |     457.27 KB |
| SelectAndMap_Main_ReusedBufferAsync | 100    |     8.326 ms |  0.5724 ms |   1.5955 ms |     7.472 ms |           - |           - |    4502.13 KB |
| SelectAndMap_Main_ReusedBufferAsync | 1000   |    31.037 ms |  3.7512 ms |  10.8231 ms |    24.973 ms |   5000.0000 |   1000.0000 |   44985.72 KB |
| SelectAndMap_Main_ReusedBufferAsync | 10000  |   337.278 ms | 16.5461 ms |  48.7865 ms |   334.254 ms |  55000.0000 |  10000.0000 |  449543.01 KB |
| SelectAndMap_Main_ReusedBufferAsync | 100000 | 3,467.848 ms | 98.9785 ms | 288.7249 ms | 3,435.619 ms | 550000.0000 | 114000.0000 | 4494685.62 KB |

New:

| Method                              | Rows   | Mean           | Error        | StdDev        | Gen0       | Gen1       | Allocated    |
|------------------------------------ |------- |---------------:|-------------:|--------------:|-----------:|-----------:|-------------:|
| SelectAndMap_Main_ReusedBufferAsync | 10     |       650.8 us |     19.56 us |      55.16 us |          - |          - |     60.55 KB |
| SelectAndMap_Main_ReusedBufferAsync | 100    |     2,833.8 us |     63.37 us |     178.72 us |          - |          - |    527.99 KB |
| SelectAndMap_Main_ReusedBufferAsync | 1000   |    24,552.9 us |  4,380.22 us |  12,777.32 us |          - |          - |   5143.66 KB |
| SelectAndMap_Main_ReusedBufferAsync | 10000  |   137,303.6 us |  7,622.68 us |  22,235.71 us |  6000.0000 |  1000.0000 |  51342.63 KB |
| SelectAndMap_Main_ReusedBufferAsync | 100000 | 3,369,344.7 us | 95,721.74 us | 282,237.74 us | 62000.0000 | 10000.0000 | 513447.63 KB |

In practice differences are still noticiable, up to 3x in terms of speed, tenfold in memory volume and ~100x in allocation events reduction can be observed (profiling of real run, not in benchmark).

… leverage simd for BMP-only strings

Reworked the rune operations to not spam char[1 or 2] allocations and…

03f1be9

… leverage simd for BMP-only strings

This was referenced Dec 29, 2025

(Improvements) Ring-buffer and XdrReaderWriter optimizations, assorted Span/Memory method additions #1253

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(Improvements) Rune related and span-ish optimizations #1247

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(Improvements) Rune operations optimization #1252

(Improvements) Rune operations optimization #1252

pl752 commented Dec 29, 2025 •

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pl752 commented Dec 29, 2025 •

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