A simple BenchmarkDotNet project that benchmarks different algorithms for string reversion (i.e. 'ABC' -> 'CBA').
Here is some results:
BenchmarkDotNet v0.14.0, Windows 11 (10.0.22631.3737/23H2/2023Update/SunValley3)
Unknown processor
.NET SDK 8.0.307
[Host] : .NET 8.0.11 (8.0.1124.51707), X64 RyuJIT AVX2
DefaultJob : .NET 8.0.11 (8.0.1124.51707), X64 RyuJIT AVX2
| Method | InputLength | Mean | Error | StdDev | Median | Gen0 | Gen1 | Allocated |
|---|---|---|---|---|---|---|---|---|
| PointerReversener | 10 | 7.479 ns | 0.1996 ns | 0.1770 ns | 7.471 ns | 0.0029 | - | 24 B |
| PointerStringCopyReversener | 10 | 15.412 ns | 0.3599 ns | 0.3367 ns | 15.392 ns | 0.0086 | - | 72 B |
| StringCreateReversener | 10 | 15.644 ns | 0.3462 ns | 0.3238 ns | 15.680 ns | 0.0086 | - | 72 B |
| ArrayReversener | 10 | 23.988 ns | 0.5143 ns | 0.5716 ns | 23.949 ns | 0.0143 | - | 120 B |
| StackSpanReversener | 10 | 26.456 ns | 0.5787 ns | 0.5413 ns | 26.621 ns | 0.0086 | - | 72 B |
| HeapSpanReversener | 10 | 26.633 ns | 0.5834 ns | 1.2433 ns | 27.142 ns | 0.0143 | - | 120 B |
| XorReversener | 10 | 30.663 ns | 0.6518 ns | 0.9756 ns | 30.742 ns | 0.0143 | - | 120 B |
| StringBuilderReversener | 10 | 39.741 ns | 0.8418 ns | 1.2073 ns | 39.724 ns | 0.0200 | - | 168 B |
| GlobalHeapPointerReversener | 10 | 141.037 ns | 2.2652 ns | 2.0081 ns | 140.796 ns | 0.0086 | - | 72 B |
| StringCreateReversener | 100 | 26.467 ns | 0.5789 ns | 0.7109 ns | 26.456 ns | 0.0296 | - | 248 B |
| ArrayReversener | 100 | 39.995 ns | 0.9862 ns | 2.9078 ns | 38.508 ns | 0.0564 | - | 472 B |
| PointerReversener | 100 | 54.064 ns | 0.7378 ns | 0.6901 ns | 53.934 ns | 0.0029 | - | 24 B |
| PointerStringCopyReversener | 100 | 66.857 ns | 1.1492 ns | 0.9596 ns | 67.107 ns | 0.0296 | - | 248 B |
| HeapSpanReversener | 100 | 96.530 ns | 1.9932 ns | 3.7438 ns | 96.041 ns | 0.0564 | - | 472 B |
| XorReversener | 100 | 133.439 ns | 2.3778 ns | 2.2242 ns | 133.384 ns | 0.0563 | - | 472 B |
| StackSpanReversener | 100 | 140.190 ns | 1.6397 ns | 1.5338 ns | 139.977 ns | 0.0296 | - | 248 B |
| StringBuilderReversener | 100 | 150.971 ns | 2.4512 ns | 2.2928 ns | 151.168 ns | 0.0620 | - | 520 B |
| GlobalHeapPointerReversener | 100 | 483.365 ns | 26.7961 ns | 78.1655 ns | 481.306 ns | 0.0296 | - | 248 B |
| StringCreateReversener | 1000 | 114.206 ns | 2.2787 ns | 3.6143 ns | 113.107 ns | 0.2449 | - | 2048 B |
| ArrayReversener | 1000 | 195.152 ns | 5.8357 ns | 16.9305 ns | 190.950 ns | 0.4866 | 0.0017 | 4072 B |
| PointerReversener | 1000 | 522.547 ns | 4.0495 ns | 3.5898 ns | 521.754 ns | 0.0029 | - | 24 B |
| PointerStringCopyReversener | 1000 | 632.353 ns | 8.6601 ns | 7.6769 ns | 634.736 ns | 0.2441 | - | 2048 B |
| HeapSpanReversener | 1000 | 725.488 ns | 13.7403 ns | 38.7547 ns | 706.105 ns | 0.4864 | 0.0010 | 4072 B |
| XorReversener | 1000 | 1,047.343 ns | 19.7775 ns | 18.4998 ns | 1,046.290 ns | 0.4864 | - | 4072 B |
| StackSpanReversener | 1000 | 1,142.372 ns | 22.2800 ns | 25.6577 ns | 1,141.060 ns | 0.2441 | - | 2048 B |
| StringBuilderReversener | 1000 | 1,250.211 ns | 19.8470 ns | 18.5649 ns | 1,249.715 ns | 0.4921 | 0.0019 | 4120 B |
| GlobalHeapPointerReversener | 1000 | 2,367.298 ns | 40.6016 ns | 35.9922 ns | 2,363.528 ns | 0.2441 | - | 2048 B |