Different methods of filling an array with the same value. Using Integer type and BenchmarkDotNet
Inspired by K.Kokosa tweet https://twitter.com/konradkokosa/status/1417760179072946176?s=09
// * Summary *
BenchmarkDotNet=v0.13.0, OS=Windows 10.0.14393.3443 (1607/AnniversaryUpdate/Redstone1)
Intel Xeon Gold 6136 CPU 3.00GHz, 2 CPU, 48 logical and 24 physical cores
Frequency=2922816 Hz, Resolution=342.1358 ns, Timer=TSC
.NET SDK=5.0.302
[Host] : .NET 5.0.8 (5.0.821.31504), X64 RyuJIT
DefaultJob : .NET 5.0.8 (5.0.821.31504), X64 RyuJIT
| Method | N | Mean | Error | StdDev | Median |
|---|---|---|---|---|---|
| ForLoop | 4 | 7.284 ns | 0.1928 ns | 0.5310 ns | 7.114 ns |
| SpanFill | 4 | 10.083 ns | 0.2347 ns | 0.5153 ns | 10.020 ns |
| ArrayFill | 4 | 8.747 ns | 0.1989 ns | 0.4952 ns | 8.620 ns |
| EnumerableRepeat | 4 | 29.256 ns | 0.6165 ns | 1.5467 ns | 28.736 ns |
| Vector | 4 | 7.459 ns | 0.1775 ns | 0.4706 ns | 7.332 ns |
| VectorUnsafe | 4 | 8.945 ns | 0.2043 ns | 0.4309 ns | 8.884 ns |
| ForLoop | 10 | 14.429 ns | 0.3186 ns | 0.7509 ns | 14.393 ns |
| SpanFill | 10 | 10.777 ns | 0.2456 ns | 0.2828 ns | 10.869 ns |
| ArrayFill | 10 | 10.433 ns | 0.2280 ns | 0.1904 ns | 10.389 ns |
| EnumerableRepeat | 10 | 33.976 ns | 0.7032 ns | 1.8401 ns | 33.605 ns |
| Vector | 10 | 8.118 ns | 0.1921 ns | 0.3102 ns | 8.000 ns |
| VectorUnsafe | 10 | 7.789 ns | 0.1783 ns | 0.1982 ns | 7.710 ns |
| ForLoop | 100 | 108.496 ns | 2.1946 ns | 2.8536 ns | 107.754 ns |
| SpanFill | 100 | 72.053 ns | 1.4693 ns | 2.4549 ns | 72.183 ns |
| ArrayFill | 100 | 95.167 ns | 1.9111 ns | 4.0727 ns | 94.535 ns |
| EnumerableRepeat | 100 | 122.987 ns | 2.7766 ns | 8.1433 ns | 121.733 ns |
| Vector | 100 | 36.494 ns | 0.7481 ns | 1.2080 ns | 36.547 ns |
| VectorUnsafe | 100 | 34.914 ns | 0.7293 ns | 1.6312 ns | 34.517 ns |
| ForLoop | 1000 | 1,005.640 ns | 20.1234 ns | 55.4258 ns | 1,001.698 ns |
| SpanFill | 1000 | 595.364 ns | 11.9092 ns | 30.3128 ns | 587.630 ns |
| ArrayFill | 1000 | 832.154 ns | 14.7162 ns | 26.9094 ns | 821.171 ns |
| EnumerableRepeat | 1000 | 871.682 ns | 17.4339 ns | 32.7451 ns | 865.868 ns |
| Vector | 1000 | 339.206 ns | 6.5463 ns | 12.9217 ns | 338.248 ns |
| VectorUnsafe | 1000 | 411.596 ns | 8.1581 ns | 18.5801 ns | 410.408 ns |
| ForLoop | 10000 | 7,765.828 ns | 146.9752 ns | 130.2897 ns | 7,761.431 ns |
| SpanFill | 10000 | 5,115.015 ns | 30.5612 ns | 27.0917 ns | 5,114.086 ns |
| ArrayFill | 10000 | 7,733.817 ns | 150.1370 ns | 166.8769 ns | 7,721.386 ns |
| EnumerableRepeat | 10000 | 6,621.446 ns | 125.1296 ns | 110.9241 ns | 6,593.316 ns |
| Vector | 10000 | 4,963.895 ns | 96.6805 ns | 94.9531 ns | 4,927.697 ns |
| VectorUnsafe | 10000 | 4,448.028 ns | 85.2660 ns | 87.5619 ns | 4,475.555 ns |
| ForLoop | 100000 | 251,181.508 ns | 2,271.9054 ns | 2,013.9849 ns | 250,332.648 ns |
| SpanFill | 100000 | 234,109.369 ns | 1,076.8504 ns | 1,007.2865 ns | 233,961.584 ns |
| ArrayFill | 100000 | 249,116.892 ns | 1,353.7727 ns | 1,200.0843 ns | 248,853.095 ns |
| EnumerableRepeat | 100000 | 242,105.290 ns | 2,108.2951 ns | 1,972.1005 ns | 241,777.499 ns |
| Vector | 100000 | 235,122.216 ns | 3,520.2854 ns | 2,939.5978 ns | 235,128.404 ns |
| VectorUnsafe | 100000 | 229,300.986 ns | 3,488.6718 ns | 3,092.6167 ns | 228,268.648 ns |
| ForLoop | 1000000 | 2,684,192.521 ns | 52,793.4705 ns | 102,969.6097 ns | 2,711,756.349 ns |
| SpanFill | 1000000 | 2,367,821.150 ns | 45,919.5188 ns | 54,663.9206 ns | 2,358,319.372 ns |
| ArrayFill | 1000000 | 2,398,216.773 ns | 42,148.2131 ns | 39,425.4647 ns | 2,387,930.157 ns |
| EnumerableRepeat | 1000000 | 2,347,596.973 ns | 46,154.1438 ns | 71,856.4414 ns | 2,318,538.734 ns |
| Vector | 1000000 | 2,256,204.245 ns | 34,031.9414 ns | 30,168.4296 ns | 2,252,355.503 ns |
| VectorUnsafe | 1000000 | 2,320,131.069 ns | 43,977.5746 ns | 50,644.6403 ns | 2,312,886.143 ns |