Audit MemoryExtensions.IndexOf variants #75754

Rob-Hague · 2022-09-16T13:46:33Z

Hi @adamsitnik, after your #73768 I am submitting a few changes which I noticed and presumed were not intentionally left out:

Add the SpanHelpers.Char specialisation to LastIndexOf(Span, ROS) to match LastIndexOf(ROS, ROS). I did not forward the Span version to ROS version to be consistent with IndexOf(Span, ROS) and IndexOf(ROS, ROS), being wary of related discussion in Vectorize {Last}IndexOf{Any} and {Last}IndexOfAnyExcept without code duplication #73768 (comment)
I did forward the LastIndexOfAny(Span, ROS) to LastIndexOfAny(ROS, ROS) to be consistent with IndexOfAny and considering the next changes:
Add more byte cases to LastIndexOfAny and IndexOfAny to be consistent with the short path

Things I noticed but did not change, deciding they were intentional:

Missing int- and long-size paths on a few variants. I saw a couple removed in that PR
Varying use of IsBitwiseEquatable vs CanVectorizeAndBenefit. I saw some tweaks in the last commit of that PR
SpanHelpers.IndexOfAnyValueType has up to 5-value versions but LastIndexOfAnyValueType has only up to 4-value

Sadly I am having a few troubles getting some benchmarks running. I will submit this as a draft until then, if you see anything I am doing obviously wrong I would appreciate the pointer (I am a rookie with the runtime repo).

edit: I was using the wrong corerun path. I changed
dotnet run -c Release -f net8.0 -- --coreRun C:\src\artifacts\bin\coreclr\windows.x64.Release\corerun.exe C:\src\runtime\artifacts\bin\coreclr\windows.x64.Release\corerun.exe

to

dotnet run -c Release -- --coreRun C:\src\artifacts\bin\testhost\net7.0-windows-Release-x64\shared\Microsoft.NETCore.App\8.0.0\corerun.exe C:\src\runtime\artifacts\bin\testhost\net7.0-windows-Release-x64\shared\Microsoft.NETCore.App\8.0.0\corerun.exe

dnfadmin · 2022-09-16T13:46:46Z

All CLA requirements met.

ghost · 2022-09-16T13:46:49Z

Tagging subscribers to this area: @dotnet/area-system-memory
See info in area-owners.md if you want to be subscribed.

Issue Details

Hi @adamsitnik, after your #73768 I am submitting a few changes which I noticed and presumed were not intentionally left out:

Add the SpanHelpers.Char specialisation to LastIndexOf(Span, ROS) to match LastIndexOf(ROS, ROS). I did not forward the Span version to ROS version to be consistent with IndexOf(Span, ROS) and IndexOf(ROS, ROS), being wary of related discussion in Vectorize {Last}IndexOf{Any} and {Last}IndexOfAnyExcept without code duplication #73768 (comment)
I did forward the LastIndexOfAny(Span, ROS) to LastIndexOfAny(ROS, ROS) to be consistent with IndexOfAny and considering the next changes:
Add more byte cases to LastIndexOfAny and IndexOfAny to be consistent with the short path

Things I noticed but did not change, deciding they were intentional:

Missing int- and long-size paths on a few variants. I saw a couple removed in that PR
Varying use of IsBitwiseEquatable vs CanVectorizeAndBenefit. I saw some tweaks in the last commit of that PR
SpanHelpers.IndexOfAnyValueType has up to 5-value versions but LastIndexOfAnyValueType has only up to 4-value

Sadly I am having a few troubles getting some benchmarks running. I will submit this as a draft until then, if you see anything I am doing obviously wrong I would appreciate the pointer (I am a rookie with the runtime repo).

I built main branch and copied the artifacts folder out to C:\src\artifacts\ then switched to my branch and built that (to C:\src\runtime\artifacts\). I am running from within my benchmark project dotnet build then
dotnet run -c Release -f net8.0 -- --coreRun C:\src\artifacts\bin\coreclr\windows.x64.Release\corerun.exe C:\src\runtime\artifacts\bin\coreclr\windows.x64.Release\corerun.exe
but I am getting output like below.

// **************************
// Benchmark: PrValidation.LastIndexOf_char_Span: Job-NLFAIL(Toolchain=\artifacts\bin\coreclr\windows.x64.Release\corerun.exe) [SearchSpaceCount=1024, SearchSpaceValue=1, ValueSpaceCount=1]
// *** Execute ***
// Launch: 1 / 1
// Execute: C:\src\artifacts\bin\coreclr\1a9e0e35-fd39-459c-800a-15f99cad96fc\corerun.exe 50419f21-5ca4-43db-985b-56f1f7210afd.dll --benchmarkName "System.Memory.PrValidation.LastIndexOf_char_Span(SearchSpaceCount: 1024, SearchSpaceValue: 1, ValueSpaceCount: 1)" --job Toolchain=\artifacts\bin\coreclr\windows.x64.Release\corerun.exe --benchmarkId 0 in C:\src\bench\bin\Release\net8.0\win-x64\50419f21-5ca4-43db-985b-56f1f7210afd\bin\Release\net8.0\publish
ExitCode != 0 and no results reported
No Workload Results were obtained from the run.
// Benchmark Process 19124 has exited with code -532462766.

dotnet --info

.NET SDK:
 Version:   8.0.100-alpha.1.22465.14
 Commit:    c09cc8aada

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.22000
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\8.0.100-alpha.1.22465.14\

Host:
  Version:      8.0.0-alpha.1.22462.15
  Architecture: x64
  Commit:       c804303ace

.NET SDKs installed:
  6.0.400 [C:\Program Files\dotnet\sdk]
  8.0.100-alpha.1.22465.14 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 6.0.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 8.0.0-alpha.1.22463.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 6.0.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 8.0.0-alpha.1.22462.15 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 6.0.8 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 8.0.0-alpha.1.22457.11 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
  x86   [C:\Program Files (x86)\dotnet]

Environment variables:
  Not set

global.json file:
  Not found

Learn more:
  https://aka.ms/dotnet/info

Download .NET:
  https://aka.ms/dotnet/download

benchmark src

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net8.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
	<RuntimeIdentifier>win-x64</RuntimeIdentifier>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="BenchmarkDotNet" Version="0.13.2" />
  </ItemGroup>

</Project>

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;
using System.Runtime.CompilerServices;
using System.Linq;
using BenchmarkDotNet.Configs;
using BenchmarkDotNet.Jobs;

namespace System.Memory
{
    public class PrValidation
    {
        //[Params(4, 64, 1024)]
        [Params(1024)]
        public int SearchSpaceCount;

        //[Params(0, 1)]
        [Params(1)]
        public int SearchSpaceValue;

        //[Params(0, 1, 2, 3, 4, 5)]
        [Params(1)]
        public int ValueSpaceCount;

        private byte[] _searchSpaceBytes, _valueSpaceBytes;
        private char[] _searchSpaceChars, _valueSpaceChars;

        [GlobalSetup]
        public void Setup()
        {
            _searchSpaceBytes = Enumerable.Repeat((byte)SearchSpaceValue, SearchSpaceCount).ToArray();
            _searchSpaceChars = Enumerable.Repeat((char)SearchSpaceValue, SearchSpaceCount).ToArray();

            _valueSpaceBytes = Enumerable.Range(1, ValueSpaceCount).Select(Convert.ToByte).ToArray();
            _valueSpaceChars = Enumerable.Range(1, ValueSpaceCount).Select(Convert.ToChar).ToArray();
        }

        [Benchmark] public void LastIndexOf_char_Span() => new Span<char>(_searchSpaceChars).LastIndexOf(_valueSpaceChars);

        // [Benchmark] public void IndexOfAny_byte_Span() => new Span<byte>(_searchSpaceBytes).IndexOfAny(_valueSpaceBytes);
        // [Benchmark] public void IndexOfAny_byte_ROS() => new ReadOnlySpan<byte>(_searchSpaceBytes).IndexOfAny(_valueSpaceBytes);

        // [Benchmark] public void LastIndexOfAny_byte_Span() => new Span<byte>(_searchSpaceBytes).LastIndexOfAny(_valueSpaceBytes);
        // [Benchmark] public void LastIndexOfAny_byte_ROS() => new ReadOnlySpan<byte>(_searchSpaceBytes).LastIndexOfAny(_valueSpaceBytes);
    }

    public class Program
    {
        public static void Main(string[] args)
        {
            BenchmarkSwitcher.FromAssembly(typeof(Program).Assembly).Run(args);
        }
    }
}

Author:	rob-hague
Assignees:	-
Labels:	`area-System.Memory`, `community-contribution`
Milestone:	-

Rob-Hague · 2022-09-16T13:49:12Z

src/libraries/System.Private.CoreLib/src/System/MemoryExtensions.cs

        public static int LastIndexOfAny<T>(this Span<T> span, ReadOnlySpan<T> values) where T : IEquatable<T>?
-        {
-            if (Unsafe.SizeOf<T>() == sizeof(byte) && RuntimeHelpers.IsBitwiseEquatable<T>())
-                return SpanHelpers.LastIndexOfAny(


This was calling the same function as the fallback

Rob-Hague · 2022-09-17T13:06:02Z

Benchmarks summary:

Regressions in IndexOfAny_byte_ROS and LastIndexOfAny_byte_ROS for 2-value
Regressions in LastIndexOfAny_byte_Span and LastIndexOfAny_char_Span for 5-value

I guess the former is related to codegen.
I guess LastIndexOfAny_byte_Span 5-value suffers from extra indirection to call the same method (there is no vectorized 5-value LastIndexOfAny).
My guess for LastIndexOfAny_char_Span 5-value is that this comes from benchmarking an unrepresentative search-space (and the probabilistic map suffers heavily from this)

I will try a more representative search space soon. In the meantime if you have any thoughts on what changes you would take (if any) please let me know. Thanks

BenchmarkDotNet=v0.13.2, OS=Windows 11 (10.0.22000.978/21H2)
AMD Ryzen 7 5700U with Radeon Graphics, 1 CPU, 16 logical and 8 physical cores
.NET SDK=8.0.100-alpha.1.22465.14
  [Host]     : .NET 8.0.0 (8.0.22.46215), X64 RyuJIT AVX2
  main : .NET 8.0.0 (42.42.42.42424), X64 RyuJIT AVX2
  PR : .NET 8.0.0 (42.42.42.42424), X64 RyuJIT AVX2

Method	Job	SearchSpaceCount	ValueSpaceCount	Mean	Error	StdDev	Median	Ratio	RatioSD
IndexOfAny_byte_ROS	main	8	1	9.830 ns	0.2249 ns	0.6156 ns	10.041 ns	1.00	0.00
IndexOfAny_byte_ROS	PR	8	1	4.971 ns	0.1001 ns	0.0937 ns	4.979 ns	0.55	0.04
IndexOfAny_byte_ROS	main	8	2	6.129 ns	0.1493 ns	0.2576 ns	5.950 ns	1.00	0.00
IndexOfAny_byte_ROS	PR	8	2	8.934 ns	0.2029 ns	0.3957 ns	8.968 ns	1.46	0.09
IndexOfAny_byte_ROS	main	8	3	9.384 ns	0.2156 ns	0.4154 ns	9.364 ns	1.00	0.00
IndexOfAny_byte_ROS	PR	8	3	9.654 ns	0.2196 ns	0.5387 ns	9.661 ns	1.03	0.08
IndexOfAny_byte_ROS	main	8	4	18.289 ns	0.3919 ns	0.7067 ns	18.407 ns	1.00	0.00
IndexOfAny_byte_ROS	PR	8	4	11.070 ns	0.2500 ns	0.5107 ns	11.093 ns	0.61	0.04
IndexOfAny_byte_ROS	main	8	5	21.680 ns	0.4553 ns	0.5592 ns	21.706 ns	1.00	0.00
IndexOfAny_byte_ROS	PR	8	5	10.146 ns	0.2242 ns	0.2399 ns	10.126 ns	0.47	0.02
IndexOfAny_byte_ROS	main	64	1	40.300 ns	0.2855 ns	0.2670 ns	40.281 ns	1.00	0.00
IndexOfAny_byte_ROS	PR	64	1	4.416 ns	0.1032 ns	0.0966 ns	4.435 ns	0.11	0.00
IndexOfAny_byte_ROS	main	64	2	4.104 ns	0.1106 ns	0.1786 ns	4.115 ns	1.00	0.00
IndexOfAny_byte_ROS	PR	64	2	5.404 ns	0.1132 ns	0.1059 ns	5.400 ns	1.32	0.07
IndexOfAny_byte_ROS	main	64	3	5.657 ns	0.1084 ns	0.1014 ns	5.677 ns	1.00	0.00
IndexOfAny_byte_ROS	PR	64	3	5.975 ns	0.1438 ns	0.2196 ns	6.006 ns	1.06	0.04
IndexOfAny_byte_ROS	main	64	4	98.455 ns	1.2650 ns	1.1833 ns	98.209 ns	1.00	0.00
IndexOfAny_byte_ROS	PR	64	4	7.705 ns	0.1821 ns	0.4364 ns	7.683 ns	0.08	0.00
IndexOfAny_byte_ROS	main	64	5	111.305 ns	0.5146 ns	0.4814 ns	111.450 ns	1.00	0.00
IndexOfAny_byte_ROS	PR	64	5	8.245 ns	0.1912 ns	0.3448 ns	8.240 ns	0.07	0.00
IndexOfAny_byte_ROS	main	1024	1	550.750 ns	0.4103 ns	0.3427 ns	550.611 ns	1.00	0.00
IndexOfAny_byte_ROS	PR	1024	1	16.185 ns	0.1722 ns	0.1611 ns	16.210 ns	0.03	0.00
IndexOfAny_byte_ROS	main	1024	2	18.040 ns	0.3859 ns	0.6657 ns	17.858 ns	1.00	0.00
IndexOfAny_byte_ROS	PR	1024	2	20.046 ns	0.4286 ns	0.4936 ns	20.117 ns	1.11	0.05
IndexOfAny_byte_ROS	main	1024	3	22.593 ns	0.3136 ns	0.2934 ns	22.444 ns	1.00	0.00
IndexOfAny_byte_ROS	PR	1024	3	22.648 ns	0.4287 ns	0.4011 ns	22.742 ns	1.00	0.03
IndexOfAny_byte_ROS	main	1024	4	1,378.781 ns	5.7639 ns	5.3915 ns	1,379.800 ns	1.00	0.00
IndexOfAny_byte_ROS	PR	1024	4	30.109 ns	0.6085 ns	0.5692 ns	30.250 ns	0.02	0.00
IndexOfAny_byte_ROS	main	1024	5	1,648.225 ns	3.7257 ns	3.1112 ns	1,648.891 ns	1.00	0.00
IndexOfAny_byte_ROS	PR	1024	5	30.211 ns	0.4717 ns	0.4412 ns	30.297 ns	0.02	0.00
LastIndexOf_char_Span	main	8	1	4.632 ns	0.0077 ns	0.0072 ns	4.630 ns	1.00	0.00
LastIndexOf_char_Span	PR	8	1	4.694 ns	0.1110 ns	0.1695 ns	4.716 ns	1.01	0.05
LastIndexOf_char_Span	main	8	2	6.081 ns	0.0035 ns	0.0029 ns	6.080 ns	1.00	0.00
LastIndexOf_char_Span	PR	8	2	6.635 ns	0.0105 ns	0.0088 ns	6.637 ns	1.09	0.00
LastIndexOf_char_Span	main	8	3	5.761 ns	0.0049 ns	0.0046 ns	5.763 ns	1.00	0.00
LastIndexOf_char_Span	PR	8	3	6.268 ns	0.0124 ns	0.0104 ns	6.266 ns	1.09	0.00
LastIndexOf_char_Span	main	8	4	5.221 ns	0.0063 ns	0.0059 ns	5.220 ns	1.00	0.00
LastIndexOf_char_Span	PR	8	4	6.004 ns	0.0035 ns	0.0032 ns	6.005 ns	1.15	0.00
LastIndexOf_char_Span	main	8	5	4.617 ns	0.0015 ns	0.0011 ns	4.617 ns	1.00	0.00
LastIndexOf_char_Span	PR	8	5	5.771 ns	0.0028 ns	0.0025 ns	5.770 ns	1.25	0.00
LastIndexOf_char_Span	main	64	1	17.617 ns	0.0112 ns	0.0099 ns	17.616 ns	1.00	0.00
LastIndexOf_char_Span	PR	64	1	5.610 ns	0.0049 ns	0.0043 ns	5.611 ns	0.32	0.00
LastIndexOf_char_Span	main	64	2	19.020 ns	0.0119 ns	0.0112 ns	19.022 ns	1.00	0.00
LastIndexOf_char_Span	PR	64	2	7.238 ns	0.0725 ns	0.0642 ns	7.253 ns	0.38	0.00
LastIndexOf_char_Span	main	64	3	18.526 ns	0.0131 ns	0.0110 ns	18.524 ns	1.00	0.00
LastIndexOf_char_Span	PR	64	3	7.215 ns	0.0510 ns	0.0477 ns	7.188 ns	0.39	0.00
LastIndexOf_char_Span	main	64	4	18.194 ns	0.0127 ns	0.0113 ns	18.192 ns	1.00	0.00
LastIndexOf_char_Span	PR	64	4	7.288 ns	0.0711 ns	0.0665 ns	7.296 ns	0.40	0.00
LastIndexOf_char_Span	main	64	5	18.095 ns	0.0253 ns	0.0237 ns	18.097 ns	1.00	0.00
LastIndexOf_char_Span	PR	64	5	7.137 ns	0.0529 ns	0.0495 ns	7.142 ns	0.39	0.00
LastIndexOf_char_Span	main	1024	1	220.402 ns	0.2264 ns	0.2118 ns	220.303 ns	1.00	0.00
LastIndexOf_char_Span	PR	1024	1	29.481 ns	0.0918 ns	0.0858 ns	29.499 ns	0.13	0.00
LastIndexOf_char_Span	main	1024	2	219.591 ns	0.3893 ns	0.3451 ns	219.559 ns	1.00	0.00
LastIndexOf_char_Span	PR	1024	2	59.159 ns	0.7284 ns	0.6813 ns	59.171 ns	0.27	0.00
LastIndexOf_char_Span	main	1024	3	218.000 ns	0.1500 ns	0.1403 ns	217.961 ns	1.00	0.00
LastIndexOf_char_Span	PR	1024	3	59.667 ns	0.3749 ns	0.3323 ns	59.617 ns	0.27	0.00
LastIndexOf_char_Span	main	1024	4	220.605 ns	0.0831 ns	0.0737 ns	220.620 ns	1.00	0.00
LastIndexOf_char_Span	PR	1024	4	59.760 ns	0.4245 ns	0.3763 ns	59.789 ns	0.27	0.00
LastIndexOf_char_Span	main	1024	5	219.007 ns	0.1947 ns	0.1626 ns	219.009 ns	1.00	0.00
LastIndexOf_char_Span	PR	1024	5	59.505 ns	0.5208 ns	0.4871 ns	59.411 ns	0.27	0.00
LastIndexOfAny_byte_ROS	main	8	1	8.740 ns	0.1974 ns	0.2027 ns	8.756 ns	1.00	0.00
LastIndexOfAny_byte_ROS	PR	8	1	5.412 ns	0.1336 ns	0.1641 ns	5.431 ns	0.62	0.02
LastIndexOfAny_byte_ROS	main	8	2	6.840 ns	0.1583 ns	0.2059 ns	6.875 ns	1.00	0.00
LastIndexOfAny_byte_ROS	PR	8	2	8.224 ns	0.1198 ns	0.1062 ns	8.235 ns	1.21	0.05
LastIndexOfAny_byte_ROS	main	8	3	9.525 ns	0.2188 ns	0.3341 ns	9.553 ns	1.00	0.00
LastIndexOfAny_byte_ROS	PR	8	3	9.984 ns	0.2122 ns	0.1985 ns	9.950 ns	1.05	0.05
LastIndexOfAny_byte_ROS	main	8	4	16.621 ns	0.3242 ns	0.3033 ns	16.816 ns	1.00	0.00
LastIndexOfAny_byte_ROS	PR	8	4	11.422 ns	0.2458 ns	0.3108 ns	11.439 ns	0.69	0.02
LastIndexOfAny_byte_ROS	main	8	5	17.627 ns	0.1521 ns	0.1422 ns	17.653 ns	1.00	0.00
LastIndexOfAny_byte_ROS	PR	8	5	18.195 ns	0.1369 ns	0.1281 ns	18.194 ns	1.03	0.01
LastIndexOfAny_byte_ROS	main	64	1	38.750 ns	0.2145 ns	0.2006 ns	38.723 ns	1.00	0.00
LastIndexOfAny_byte_ROS	PR	64	1	4.607 ns	0.1005 ns	0.0891 ns	4.613 ns	0.12	0.00
LastIndexOfAny_byte_ROS	main	64	2	4.612 ns	0.1186 ns	0.1584 ns	4.656 ns	1.00	0.00
LastIndexOfAny_byte_ROS	PR	64	2	5.156 ns	0.0731 ns	0.0684 ns	5.193 ns	1.12	0.04
LastIndexOfAny_byte_ROS	main	64	3	5.537 ns	0.1178 ns	0.1102 ns	5.542 ns	1.00	0.00
LastIndexOfAny_byte_ROS	PR	64	3	6.040 ns	0.1475 ns	0.3012 ns	6.163 ns	1.08	0.07
LastIndexOfAny_byte_ROS	main	64	4	98.505 ns	0.6669 ns	0.6238 ns	98.666 ns	1.00	0.00
LastIndexOfAny_byte_ROS	PR	64	4	7.229 ns	0.1715 ns	0.3424 ns	7.249 ns	0.07	0.00
LastIndexOfAny_byte_ROS	main	64	5	109.523 ns	0.1604 ns	0.1500 ns	109.560 ns	1.00	0.00
LastIndexOfAny_byte_ROS	PR	64	5	111.629 ns	0.1737 ns	0.1624 ns	111.664 ns	1.02	0.00
LastIndexOfAny_byte_ROS	main	1024	1	548.149 ns	0.4610 ns	0.4313 ns	548.020 ns	1.00	0.00
LastIndexOfAny_byte_ROS	PR	1024	1	17.031 ns	0.0456 ns	0.0426 ns	17.028 ns	0.03	0.00
LastIndexOfAny_byte_ROS	main	1024	2	20.863 ns	0.3697 ns	0.3458 ns	20.693 ns	1.00	0.00
LastIndexOfAny_byte_ROS	PR	1024	2	18.833 ns	0.2013 ns	0.1883 ns	18.859 ns	0.90	0.02
LastIndexOfAny_byte_ROS	main	1024	3	21.567 ns	0.2792 ns	0.2612 ns	21.573 ns	1.00	0.00
LastIndexOfAny_byte_ROS	PR	1024	3	21.688 ns	0.4454 ns	0.4766 ns	21.688 ns	1.00	0.03
LastIndexOfAny_byte_ROS	main	1024	4	1,371.158 ns	8.6512 ns	8.0923 ns	1,372.419 ns	1.00	0.00
LastIndexOfAny_byte_ROS	PR	1024	4	29.946 ns	0.3665 ns	0.3428 ns	30.049 ns	0.02	0.00
LastIndexOfAny_byte_ROS	main	1024	5	1,644.423 ns	2.4255 ns	2.2688 ns	1,644.547 ns	1.00	0.00
LastIndexOfAny_byte_ROS	PR	1024	5	1,691.436 ns	39.6828 ns	105.9215 ns	1,646.512 ns	1.07	0.11
LastIndexOfAny_byte_Span	main	8	1	7.177 ns	0.0663 ns	0.0621 ns	7.179 ns	1.00	0.00
LastIndexOfAny_byte_Span	PR	8	1	5.121 ns	0.0870 ns	0.0771 ns	5.122 ns	0.71	0.02
LastIndexOfAny_byte_Span	main	8	2	10.563 ns	0.1535 ns	0.1436 ns	10.639 ns	1.00	0.00
LastIndexOfAny_byte_Span	PR	8	2	9.301 ns	0.2136 ns	0.4012 ns	9.432 ns	0.88	0.04
LastIndexOfAny_byte_Span	main	8	3	13.617 ns	0.2393 ns	0.2238 ns	13.631 ns	1.00	0.00
LastIndexOfAny_byte_Span	PR	8	3	10.058 ns	0.1335 ns	0.1183 ns	10.039 ns	0.74	0.01
LastIndexOfAny_byte_Span	main	8	4	16.143 ns	0.2179 ns	0.2038 ns	16.174 ns	1.00	0.00
LastIndexOfAny_byte_Span	PR	8	4	12.045 ns	0.1427 ns	0.1265 ns	12.010 ns	0.75	0.01
LastIndexOfAny_byte_Span	main	8	5	17.577 ns	0.1953 ns	0.1631 ns	17.554 ns	1.00	0.00
LastIndexOfAny_byte_Span	PR	8	5	26.138 ns	0.7270 ns	2.1437 ns	27.469 ns	1.45	0.12
LastIndexOfAny_byte_Span	main	64	1	38.526 ns	0.1101 ns	0.1030 ns	38.559 ns	1.00	0.00
LastIndexOfAny_byte_Span	PR	64	1	4.531 ns	0.0941 ns	0.0880 ns	4.552 ns	0.12	0.00
LastIndexOfAny_byte_Span	main	64	2	59.828 ns	0.1546 ns	0.1291 ns	59.875 ns	1.00	0.00
LastIndexOfAny_byte_Span	PR	64	2	5.825 ns	0.1112 ns	0.1041 ns	5.802 ns	0.10	0.00
LastIndexOfAny_byte_Span	main	64	3	78.977 ns	1.6081 ns	1.7207 ns	78.920 ns	1.00	0.00
LastIndexOfAny_byte_Span	PR	64	3	6.372 ns	0.1522 ns	0.2665 ns	6.466 ns	0.08	0.00
LastIndexOfAny_byte_Span	main	64	4	92.914 ns	0.2358 ns	0.2206 ns	92.887 ns	1.00	0.00
LastIndexOfAny_byte_Span	PR	64	4	7.106 ns	0.1092 ns	0.1021 ns	7.093 ns	0.08	0.00
LastIndexOfAny_byte_Span	main	64	5	115.788 ns	0.4738 ns	0.4200 ns	115.776 ns	1.00	0.00
LastIndexOfAny_byte_Span	PR	64	5	178.753 ns	2.8791 ns	2.4042 ns	178.450 ns	1.54	0.02
LastIndexOfAny_byte_Span	main	1024	1	546.179 ns	0.7525 ns	0.7039 ns	546.434 ns	1.00	0.00
LastIndexOfAny_byte_Span	PR	1024	1	15.804 ns	0.2782 ns	0.2603 ns	15.831 ns	0.03	0.00
LastIndexOfAny_byte_Span	main	1024	2	826.460 ns	0.4934 ns	0.4374 ns	826.339 ns	1.00	0.00
LastIndexOfAny_byte_Span	PR	1024	2	22.172 ns	0.4427 ns	0.4546 ns	22.202 ns	0.03	0.00
LastIndexOfAny_byte_Span	main	1024	3	1,116.313 ns	13.1206 ns	12.2730 ns	1,118.085 ns	1.00	0.00
LastIndexOfAny_byte_Span	PR	1024	3	23.311 ns	0.4563 ns	0.4268 ns	23.179 ns	0.02	0.00
LastIndexOfAny_byte_Span	main	1024	4	1,377.804 ns	8.4186 ns	7.8747 ns	1,377.064 ns	1.00	0.00
LastIndexOfAny_byte_Span	PR	1024	4	30.467 ns	0.1921 ns	0.1703 ns	30.499 ns	0.02	0.00
LastIndexOfAny_byte_Span	main	1024	5	1,639.299 ns	3.6586 ns	3.4223 ns	1,639.443 ns	1.00	0.00
LastIndexOfAny_byte_Span	PR	1024	5	1,639.896 ns	2.3544 ns	2.0871 ns	1,639.982 ns	1.00	0.00
LastIndexOfAny_char_ROS	main	8	1	4.176 ns	0.1122 ns	0.2753 ns	4.304 ns	1.00	0.00
LastIndexOfAny_char_ROS	PR	8	1	4.118 ns	0.1111 ns	0.2908 ns	4.198 ns	0.99	0.09
LastIndexOfAny_char_ROS	main	8	2	4.153 ns	0.1100 ns	0.1391 ns	4.225 ns	1.00	0.00
LastIndexOfAny_char_ROS	PR	8	2	4.123 ns	0.1131 ns	0.2336 ns	4.225 ns	1.00	0.06
LastIndexOfAny_char_ROS	main	8	3	5.568 ns	0.1368 ns	0.1827 ns	5.593 ns	1.00	0.00
LastIndexOfAny_char_ROS	PR	8	3	5.579 ns	0.1354 ns	0.1854 ns	5.606 ns	1.00	0.05
LastIndexOfAny_char_ROS	main	8	4	5.926 ns	0.1444 ns	0.2452 ns	5.906 ns	1.00	0.00
LastIndexOfAny_char_ROS	PR	8	4	6.054 ns	0.1478 ns	0.2345 ns	6.197 ns	1.02	0.06
LastIndexOfAny_char_ROS	main	8	5	30.105 ns	0.3593 ns	0.3361 ns	30.278 ns	1.00	0.00
LastIndexOfAny_char_ROS	PR	8	5	28.813 ns	0.1247 ns	0.1166 ns	28.858 ns	0.96	0.01
LastIndexOfAny_char_ROS	main	64	1	5.117 ns	0.1311 ns	0.3500 ns	5.114 ns	1.00	0.00
LastIndexOfAny_char_ROS	PR	64	1	5.322 ns	0.1344 ns	0.2093 ns	5.392 ns	1.04	0.10
LastIndexOfAny_char_ROS	main	64	2	5.861 ns	0.1349 ns	0.1261 ns	5.918 ns	1.00	0.00
LastIndexOfAny_char_ROS	PR	64	2	5.945 ns	0.1455 ns	0.1361 ns	5.968 ns	1.01	0.03
LastIndexOfAny_char_ROS	main	64	3	8.693 ns	0.2009 ns	0.2945 ns	8.722 ns	1.00	0.00
LastIndexOfAny_char_ROS	PR	64	3	8.670 ns	0.1939 ns	0.2233 ns	8.704 ns	1.00	0.06
LastIndexOfAny_char_ROS	main	64	4	9.198 ns	0.2122 ns	0.4746 ns	9.419 ns	1.00	0.00
LastIndexOfAny_char_ROS	PR	64	4	9.363 ns	0.2149 ns	0.4763 ns	9.568 ns	1.02	0.08
LastIndexOfAny_char_ROS	main	64	5	165.454 ns	0.4546 ns	0.4253 ns	165.417 ns	1.00	0.00
LastIndexOfAny_char_ROS	PR	64	5	163.399 ns	0.1426 ns	0.1334 ns	163.397 ns	0.99	0.00
LastIndexOfAny_char_ROS	main	1024	1	30.605 ns	0.4445 ns	0.4158 ns	30.534 ns	1.00	0.00
LastIndexOfAny_char_ROS	PR	1024	1	30.494 ns	0.6011 ns	0.5623 ns	30.541 ns	1.00	0.02
LastIndexOfAny_char_ROS	main	1024	2	35.341 ns	0.3629 ns	0.3395 ns	35.478 ns	1.00	0.00
LastIndexOfAny_char_ROS	PR	1024	2	35.433 ns	0.2929 ns	0.2740 ns	35.524 ns	1.00	0.01
LastIndexOfAny_char_ROS	main	1024	3	51.550 ns	0.1107 ns	0.0981 ns	51.550 ns	1.00	0.00
LastIndexOfAny_char_ROS	PR	1024	3	51.553 ns	0.2292 ns	0.2032 ns	51.633 ns	1.00	0.00
LastIndexOfAny_char_ROS	main	1024	4	52.702 ns	0.5584 ns	0.5223 ns	52.951 ns	1.00	0.00
LastIndexOfAny_char_ROS	PR	1024	4	52.687 ns	0.6479 ns	0.6061 ns	52.992 ns	1.00	0.02
LastIndexOfAny_char_ROS	main	1024	5	2,402.390 ns	6.0446 ns	5.6541 ns	2,400.650 ns	1.00	0.00
LastIndexOfAny_char_ROS	PR	1024	5	2,400.704 ns	3.5544 ns	2.9681 ns	2,399.535 ns	1.00	0.00
LastIndexOfAny_char_Span	main	8	1	6.727 ns	0.0787 ns	0.0698 ns	6.737 ns	1.00	0.00
LastIndexOfAny_char_Span	PR	8	1	3.637 ns	0.1023 ns	0.3015 ns	3.727 ns	0.55	0.05
LastIndexOfAny_char_Span	main	8	2	8.841 ns	0.0080 ns	0.0075 ns	8.840 ns	1.00	0.00
LastIndexOfAny_char_Span	PR	8	2	4.405 ns	0.1111 ns	0.1628 ns	4.505 ns	0.49	0.02
LastIndexOfAny_char_Span	main	8	3	11.014 ns	0.0100 ns	0.0089 ns	11.012 ns	1.00	0.00
LastIndexOfAny_char_Span	PR	8	3	5.497 ns	0.1366 ns	0.2663 ns	5.504 ns	0.49	0.02
LastIndexOfAny_char_Span	main	8	4	12.962 ns	0.0631 ns	0.0590 ns	12.944 ns	1.00	0.00
LastIndexOfAny_char_Span	PR	8	4	6.496 ns	0.1553 ns	0.1789 ns	6.500 ns	0.50	0.01
LastIndexOfAny_char_Span	main	8	5	15.172 ns	0.0622 ns	0.0581 ns	15.181 ns	1.00	0.00
LastIndexOfAny_char_Span	PR	8	5	29.214 ns	0.1136 ns	0.1062 ns	29.259 ns	1.93	0.01
LastIndexOfAny_char_Span	main	64	1	37.689 ns	0.0323 ns	0.0302 ns	37.682 ns	1.00	0.00
LastIndexOfAny_char_Span	PR	64	1	4.564 ns	0.1197 ns	0.2218 ns	4.643 ns	0.12	0.01
LastIndexOfAny_char_Span	main	64	2	58.640 ns	0.1044 ns	0.0925 ns	58.613 ns	1.00	0.00
LastIndexOfAny_char_Span	PR	64	2	5.953 ns	0.0897 ns	0.0700 ns	5.974 ns	0.10	0.00
LastIndexOfAny_char_Span	main	64	3	76.896 ns	0.4778 ns	0.4469 ns	76.845 ns	1.00	0.00
LastIndexOfAny_char_Span	PR	64	3	9.166 ns	0.2175 ns	0.6414 ns	9.171 ns	0.12	0.01
LastIndexOfAny_char_Span	main	64	4	91.639 ns	0.3216 ns	0.3009 ns	91.635 ns	1.00	0.00
LastIndexOfAny_char_Span	PR	64	4	10.127 ns	0.1005 ns	0.0940 ns	10.151 ns	0.11	0.00
LastIndexOfAny_char_Span	main	64	5	109.354 ns	0.2167 ns	0.2027 ns	109.332 ns	1.00	0.00
LastIndexOfAny_char_Span	PR	64	5	165.458 ns	1.4240 ns	1.3320 ns	165.469 ns	1.51	0.01
LastIndexOfAny_char_Span	main	1024	1	552.382 ns	0.2771 ns	0.2314 ns	552.404 ns	1.00	0.00
LastIndexOfAny_char_Span	PR	1024	1	29.888 ns	0.1588 ns	0.1486 ns	29.938 ns	0.05	0.00
LastIndexOfAny_char_Span	main	1024	2	826.694 ns	0.8303 ns	0.7767 ns	826.598 ns	1.00	0.00
LastIndexOfAny_char_Span	PR	1024	2	32.428 ns	0.0896 ns	0.0838 ns	32.427 ns	0.04	0.00
LastIndexOfAny_char_Span	main	1024	3	1,418.347 ns	86.3344 ns	254.5588 ns	1,636.604 ns	1.00	0.00
LastIndexOfAny_char_Span	PR	1024	3	52.653 ns	0.6295 ns	0.5888 ns	52.679 ns	0.04	0.01
LastIndexOfAny_char_Span	main	1024	4	1,373.643 ns	6.0041 ns	5.0137 ns	1,373.256 ns	1.00	0.00
LastIndexOfAny_char_Span	PR	1024	4	52.931 ns	0.3968 ns	0.3712 ns	52.740 ns	0.04	0.00
LastIndexOfAny_char_Span	main	1024	5	1,659.335 ns	2.3113 ns	1.8045 ns	1,659.399 ns	1.00	0.00
LastIndexOfAny_char_Span	PR	1024	5	2,408.283 ns	8.3724 ns	7.8315 ns	2,405.072 ns	1.45	0.00

public class PrValidation
{
    [Params(8, 64, 1024)]
    public int SearchSpaceCount;

    [Params(1, 2, 3, 4, 5)]
    public int ValueSpaceCount;

    private byte[] _searchSpaceBytes, _valueSpaceBytes;
    private char[] _searchSpaceChars, _valueSpaceChars;

    [GlobalSetup]
    public void Setup()
    {
        _searchSpaceBytes = new byte[SearchSpaceCount];
        _searchSpaceChars = new char[SearchSpaceCount];

        _valueSpaceBytes = Enumerable.Range(1, ValueSpaceCount).Select(Convert.ToByte).ToArray();
        _valueSpaceChars = Enumerable.Range(1, ValueSpaceCount).Select(Convert.ToChar).ToArray();
    }

    [Benchmark] public void LastIndexOf_char_Span() => new Span<char>(_searchSpaceChars).LastIndexOf(_valueSpaceChars);

    [Benchmark] public void IndexOfAny_byte_ROS() => new ReadOnlySpan<byte>(_searchSpaceBytes).IndexOfAny(_valueSpaceBytes);

    [Benchmark] public void LastIndexOfAny_byte_Span() => new Span<byte>(_searchSpaceBytes).LastIndexOfAny(_valueSpaceBytes);
    [Benchmark] public void LastIndexOfAny_byte_ROS() => new ReadOnlySpan<byte>(_searchSpaceBytes).LastIndexOfAny(_valueSpaceBytes);
    
    [Benchmark] public void LastIndexOfAny_char_Span() => new Span<char>(_searchSpaceChars).LastIndexOfAny(_valueSpaceChars);
    [Benchmark] public void LastIndexOfAny_char_ROS() => new ReadOnlySpan<char>(_searchSpaceChars).LastIndexOfAny(_valueSpaceChars);
}

Rob-Hague · 2022-09-18T17:41:09Z

I ran some slightly more comprehensive benchmarks on LastIndexOfAny 5-value. Really the changes are just unifying the Span and ReadOnlySpan versions which I presume is supposed to be the case and I am only submitting them in the context of correcting a mistake rather than any optimisation opportunity. So the benchmarks are just for completeness sake (and curiosity).

BenchmarkDotNet=v0.13.2, OS=Windows 11 (10.0.22000.978/21H2)
AMD Ryzen 7 5700U with Radeon Graphics, 1 CPU, 16 logical and 8 physical cores
.NET SDK=8.0.100-alpha.1.22465.14
  [Host]     : .NET 8.0.0 (8.0.22.46215), X64 RyuJIT AVX2
  main : .NET 8.0.0 (42.42.42.42424), X64 RyuJIT AVX2
  PR : .NET 8.0.0 (42.42.42.42424), X64 RyuJIT AVX2

Method	Job	SearchSpaceCount	valueSpace	Mean	Error	StdDev	Median	Ratio	RatioSD
LastIndexOfAny_Span	main	10	\r\n\t\\\"	27.804 ns	0.5796 ns	1.3082 ns	27.910 ns	1.00	0.00
LastIndexOfAny_Span	PR	10	\r\n\t\\\"	16.236 ns	0.1208 ns	0.1130 ns	16.286 ns	0.60	0.03

LastIndexOfAny_ROS	main	10	\r\n\t\\\"	15.309 ns	0.1546 ns	0.1447 ns	15.357 ns	1.00	0.00
LastIndexOfAny_ROS	PR	10	\r\n\t\\\"	15.421 ns	0.1328 ns	0.1242 ns	15.466 ns	1.01	0.01

LastIndexOfAny_Span	main	10	LWXYZ	27.230 ns	0.8606 ns	2.5374 ns	26.416 ns	1.00	0.00
LastIndexOfAny_Span	PR	10	LWXYZ	17.270 ns	0.1064 ns	0.0996 ns	17.313 ns	0.66	0.05

LastIndexOfAny_ROS	main	10	LWXYZ	16.384 ns	0.0820 ns	0.0767 ns	16.433 ns	1.00	0.00
LastIndexOfAny_ROS	PR	10	LWXYZ	16.341 ns	0.1697 ns	0.1587 ns	16.401 ns	1.00	0.01

LastIndexOfAny_Span	main	10	abcde	14.497 ns	0.1948 ns	0.1727 ns	14.422 ns	1.00	0.00
LastIndexOfAny_Span	PR	10	abcde	16.428 ns	0.1138 ns	0.1065 ns	16.439 ns	1.13	0.02

LastIndexOfAny_ROS	main	10	abcde	15.460 ns	0.1171 ns	0.1095 ns	15.515 ns	1.00	0.00
LastIndexOfAny_ROS	PR	10	abcde	15.429 ns	0.1387 ns	0.1298 ns	15.469 ns	1.00	0.01

LastIndexOfAny_Span	main	10	zzzzu	3.325 ns	0.0305 ns	0.0270 ns	3.323 ns	1.00	0.00
LastIndexOfAny_Span	PR	10	zzzzu	12.517 ns	0.1053 ns	0.0985 ns	12.548 ns	3.77	0.05

LastIndexOfAny_ROS	main	10	zzzzu	11.752 ns	0.1259 ns	0.1051 ns	11.768 ns	1.00	0.00
LastIndexOfAny_ROS	PR	10	zzzzu	11.853 ns	0.2234 ns	0.2090 ns	11.757 ns	1.01	0.02

LastIndexOfAny_Span	main	100	\r\n\t"	250.333 ns	5.0276 ns	11.8508 ns	249.235 ns	1.00	0.00
LastIndexOfAny_Span	PR	100	\r\n\t"	82.828 ns	0.1629 ns	0.1360 ns	82.841 ns	0.33	0.02

LastIndexOfAny_ROS	main	100	\r\n\t"	75.268 ns	0.1356 ns	0.1268 ns	75.216 ns	1.00	0.00
LastIndexOfAny_ROS	PR	100	\r\n\t"	74.259 ns	0.1841 ns	0.1722 ns	74.271 ns	0.99	0.00

LastIndexOfAny_Span	main	100	LWXYZ	295.952 ns	13.6564 ns	40.2662 ns	292.568 ns	1.00	0.00
LastIndexOfAny_Span	PR	100	LWXYZ	87.481 ns	1.2991 ns	1.2152 ns	87.459 ns	0.35	0.04

LastIndexOfAny_ROS	main	100	LWXYZ	79.039 ns	0.2940 ns	0.2750 ns	79.073 ns	1.00	0.00
LastIndexOfAny_ROS	PR	100	LWXYZ	79.330 ns	0.4195 ns	0.3924 ns	79.323 ns	1.00	0.00

LastIndexOfAny_Span	main	100	abcde	8.767 ns	0.1342 ns	0.1120 ns	8.772 ns	1.00	0.00
LastIndexOfAny_Span	PR	100	abcde	13.302 ns	0.1049 ns	0.0981 ns	13.350 ns	1.52	0.03

LastIndexOfAny_ROS	main	100	abcde	12.582 ns	0.1828 ns	0.1710 ns	12.606 ns	1.00	0.00
LastIndexOfAny_ROS	PR	100	abcde	12.525 ns	0.1695 ns	0.1586 ns	12.584 ns	1.00	0.02

LastIndexOfAny_Span	main	100	zzzzu	8.908 ns	0.2076 ns	0.5014 ns	9.091 ns	1.00	0.00
LastIndexOfAny_Span	PR	100	zzzzu	13.690 ns	0.1475 ns	0.1380 ns	13.731 ns	1.54	0.10

LastIndexOfAny_ROS	main	100	zzzzu	12.846 ns	0.2601 ns	0.2433 ns	12.949 ns	1.00	0.00
LastIndexOfAny_ROS	PR	100	zzzzu	12.885 ns	0.1873 ns	0.1752 ns	12.920 ns	1.00	0.02

LastIndexOfAny_Span	main	1000	\r\n\t"	526.045 ns	4.8075 ns	4.2617 ns	527.380 ns	1.00	0.00
LastIndexOfAny_Span	PR	1000	\r\n\t"	207.644 ns	0.0942 ns	0.0787 ns	207.641 ns	0.39	0.00

LastIndexOfAny_ROS	main	1000	\r\n\t"	183.971 ns	0.3338 ns	0.2959 ns	184.048 ns	1.00	0.00
LastIndexOfAny_ROS	PR	1000	\r\n\t"	184.128 ns	0.2943 ns	0.2609 ns	184.171 ns	1.00	0.00

LastIndexOfAny_Span	main	1000	LWXYZ	2,190.996 ns	145.3601 ns	428.5975 ns	2,315.091 ns	1.00	0.00
LastIndexOfAny_Span	PR	1000	LWXYZ	640.646 ns	0.2470 ns	0.2311 ns	640.625 ns	0.28	0.02

LastIndexOfAny_ROS	main	1000	LWXYZ	561.617 ns	0.5231 ns	0.4637 ns	561.710 ns	1.00	0.00
LastIndexOfAny_ROS	PR	1000	LWXYZ	561.928 ns	0.3935 ns	0.3681 ns	561.968 ns	1.00	0.00

LastIndexOfAny_Span	main	1000	abcde	10.516 ns	0.2370 ns	0.2910 ns	10.596 ns	1.00	0.00
LastIndexOfAny_Span	PR	1000	abcde	14.389 ns	0.1549 ns	0.1449 ns	14.413 ns	1.37	0.04

LastIndexOfAny_ROS	main	1000	abcde	13.649 ns	0.1730 ns	0.1618 ns	13.717 ns	1.00	0.00
LastIndexOfAny_ROS	PR	1000	abcde	13.523 ns	0.2902 ns	0.2715 ns	13.618 ns	0.99	0.02

LastIndexOfAny_Span	main	1000	zzzzu	11.171 ns	0.1732 ns	0.1621 ns	11.212 ns	1.00	0.00
LastIndexOfAny_Span	PR	1000	zzzzu	15.124 ns	0.1184 ns	0.1108 ns	15.155 ns	1.35	0.02

LastIndexOfAny_ROS	main	1000	zzzzu	14.606 ns	0.1404 ns	0.1313 ns	14.625 ns	1.00	0.00
LastIndexOfAny_ROS	PR	1000	zzzzu	14.626 ns	0.1390 ns	0.1300 ns	14.686 ns	1.00	0.01

    public class LoremIpsum
    {
        [Params(10, 100, 1000)]
        public int SearchSpaceCount;

        private char[] _searchSpace;

        [GlobalSetup]
        public void Setup()
        {
            _searchSpace = _loremIpsum.AsSpan(0, SearchSpaceCount).ToArray();
        }

        [Benchmark]
        [ArgumentsSource(nameof(ValueSpaces))]
        public int LastIndexOfAny_Span(string valueSpace) => new Span<char>(_searchSpace).LastIndexOfAny(valueSpace);

        [Benchmark]
        [ArgumentsSource(nameof(ValueSpaces))]
        public int LastIndexOfAny_ROS(string valueSpace) => new ReadOnlySpan<char>(_searchSpace).LastIndexOfAny(valueSpace);

        public IEnumerable<object> ValueSpaces()
        {
            yield return "\r\n\t\\\""; // (-1, -1, 724) in _searchSpace.AsSpan(0, SearchSpaceCount)
            yield return "abcde"; // (3, 96, 996)
            yield return "zzzzu"; // (-1, 57, 899)
            yield return "LWXYZ"; // (0, 0, 101)
        }

        private readonly string _loremIpsum = @"Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam sodales orci at urna efficitur finibus. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Aenean ultrices facilisis volutpat. Curabitur vel sollicitudin risus. Nunc tortor libero, pretium ut mi eu, finibus rutrum enim. Vivamus malesuada vel nunc eu faucibus. Aliquam volutpat ultrices risus non pellentesque. Vivamus dignissim augue non dignissim pellentesque. Duis a fermentum dui. Nullam quis vestibulum neque. Quisque euismod ligula in ex blandit, sed aliquam orci lacinia. Curabitur facilisis, ante cursus venenatis dictum, elit ante rutrum nibh, vitae maximus libero odio ac est. Aliquam dignissim eros quis congue convallis. Aenean et erat libero.

Donec sapien nisl, efficitur nec arcu non, convallis fringilla nunc. Aenean rhoncus, tortor quis imperdiet placerat, dui nibh accumsan felis, sed mattis odio lectus sed est. Nulla cursus dictum sodales. Maecenas eget ornare augue, sed aliquam mauris. Fusce vel nisl congue, porta elit et, semper lectus.";

    }

This method is updated to match LastIndexOf(ROS, ROS)

This is consistent with IndexOfAny(Span, ROS)

Rob-Hague · 2022-09-28T13:35:53Z

ping @adamsitnik not sure if you saw this one (which was unfortunately timed amongst the other IndexOf fixes), or if you otherwise had any thoughts. Thanks

adamsitnik

Thank you for a very thoughtful audit of all MemoryExtensions overloads! And apologies for the delay in review.

The PR looks great to me, failures are unrelated. Merging!

MihaZupan · 2022-10-26T14:54:38Z

src/libraries/System.Private.CoreLib/src/System/MemoryExtensions.cs

@@ -1478,18 +1518,8 @@ private static unsafe int IndexOfAnyProbabilistic(ref char searchSpace, int sear
        /// </summary>
        /// <param name="span">The span to search.</param>
        /// <param name="values">The set of values to search for.</param>
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]


@Rob-Hague @adamsitnik
Was this intentional?

For better or worse, the LastIndexOfAny(ROS) overload is marked with AggressiveInlining, so this Span overload will now be more expensive for const values.

At the very least, it's now even more inconsistent with other places (e.g. IndexOfAny).

It was intentional in that it became consistent with many of the other Span to ROS forwards though I agree it is (now) inconsistent with IndexOfAny(Span, ROS). I probably overlooked that.

I also believed that the annotation was superfluous in such cases - I apologise for the assumption as I did not instrument that.

AndyAyersMS · 2022-11-03T16:54:03Z

Improvements:

[Perf] Windows/arm64: 2 Improvements on 10/26/2022 10:56:11 AM perf-autofiling-issues#9474
[Perf] Windows/arm64: 2 Improvements on 10/26/2022 10:56:11 AM perf-autofiling-issues#9267

ghost added the community-contribution Indicates that the PR has been added by a community member label Sep 16, 2022

dotnet-issue-labeler bot added the area-System.Memory label Sep 16, 2022

Rob-Hague commented Sep 16, 2022

View reviewed changes

Rob-Hague marked this pull request as ready for review September 17, 2022 13:06

Rob-Hague added 3 commits September 22, 2022 20:26

Add missing char specialisation to LastIndexOf(Span, ROS)

5f19a1f

This method is updated to match LastIndexOf(ROS, ROS)

Forward LastIndexOfAny(Span, ROS) to (ROS, ROS) version

3ce1ea2

This is consistent with IndexOfAny(Span, ROS)

Add missing special cases for {Last}IndexOfAny<byte>(ROS, ROS)

cc8bd94

Rob-Hague force-pushed the indexofaudit branch from 70091fc to cc8bd94 Compare September 22, 2022 18:57

adamsitnik self-assigned this Oct 26, 2022

adamsitnik approved these changes Oct 26, 2022

View reviewed changes

adamsitnik merged commit 3e40074 into dotnet:main Oct 26, 2022

adamsitnik added the tenet-performance Performance related issue label Oct 26, 2022

adamsitnik added this to the 8.0.0 milestone Oct 26, 2022

MihaZupan reviewed Oct 26, 2022

View reviewed changes

Rob-Hague deleted the indexofaudit branch October 26, 2022 20:48

MihaZupan mentioned this pull request Nov 2, 2022

Vectorize {Last}IndexOfAny{Except} for ASCII needles #76740

Merged

stephentoub mentioned this pull request Nov 4, 2022

[Perf] Windows/x64: 1 Regression in IndexOfAny #77906

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Audit MemoryExtensions.IndexOf variants #75754

Audit MemoryExtensions.IndexOf variants #75754

Rob-Hague commented Sep 16, 2022 •

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dnfadmin commented Sep 16, 2022 •

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ghost commented Sep 16, 2022

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Rob-Hague commented Sep 28, 2022

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MihaZupan Oct 26, 2022 •

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Rob-Hague Oct 26, 2022

AndyAyersMS commented Nov 3, 2022 •

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Audit MemoryExtensions.IndexOf variants #75754

Audit MemoryExtensions.IndexOf variants #75754

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Rob-Hague commented Sep 16, 2022 • edited Loading

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Rob-Hague commented Sep 16, 2022 •

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dnfadmin commented Sep 16, 2022 •

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Rob-Hague commented Sep 17, 2022 •

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Rob-Hague commented Sep 18, 2022 •

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MihaZupan Oct 26, 2022 •

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AndyAyersMS commented Nov 3, 2022 •

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