Add ScatterStore and GatherLoad to SVE microbenchmark

src/benchmarks/micro/sve/GatherLoad.cs

@@ -0,0 +1,104 @@
+using System;
+using System.Diagnostics;
+using System.Numerics;
+using System.Runtime.Intrinsics;
+using System.Runtime.Intrinsics.Arm;
+using BenchmarkDotNet.Attributes;
+using BenchmarkDotNet.Extensions;
+using BenchmarkDotNet.Configs;
+using BenchmarkDotNet.Filters;
+using MicroBenchmarks;
+
+namespace SveBenchmarks
+{
+    [BenchmarkCategory(Categories.Runtime)]
+    [OperatingSystemsArchitectureFilter(allowed: true, System.Runtime.InteropServices.Architecture.Arm64)]
+    [Config(typeof(Config))]
+    public class GatherLoad
+    {
+        private class Config : ManualConfig
+        {
+            public Config()
+            {
+                AddFilter(new SimpleFilter(_ => Sve.IsSupported));
+            }
+        }
+
+        [Params(15, 127, 527, 10015)]
+        public int Size;
+
+        private uint[] _objects;
+        private uint[] _indices;
+        private ulong _result;
+
+        [GlobalSetup]
+        public virtual void Setup()
+        {
+            _objects = ValuesGenerator.Array<uint>(Size);
+            _indices = ValuesGenerator.Array<uint>(Size);
+            for (int i = 0; i < Size; i++)
+            {
+                _indices[i] %= (uint)Size;
+            }
+        }
+
+        [GlobalCleanup]
+        public virtual void Verify()
+        {
+            ulong current = _result;
+            Setup();
+            Scalar();
+            ulong scalar = _result;
+            // Check that the result is the same as the scalar result.
+            Debug.Assert(current == scalar);
+        }
+
+        // The following algorithms are adapted from the Arm simd-loops repository:
+        // https://gitlab.arm.com/architecture/simd-loops/-/blob/main/loops/loop_023.c
+
+        [Benchmark]
+        public unsafe void Scalar()
+        {
+            fixed (uint* objects = _objects, indices = _indices)
+            {
+                ulong res = 0;
+                for (int i = 0; i < Size; i++)
+                {
+                    res += objects[indices[i]];
+                }
+                _result = res;
+            }
+        }
+
+        [Benchmark]
+        public unsafe void SveGatherLoad()
+        {
+            fixed (uint* objects = _objects, indices = _indices)
+            {
+                int i = 0;
+                int cntw = (int)Sve.Count32BitElements();
+
+                Vector<uint> ones = Vector<uint>.One;
+                Vector<uint> resVec = Vector<uint>.Zero;
+                Vector<uint> pTrue = Sve.CreateTrueMaskUInt32();
+                Vector<uint> pLoop = Sve.CreateWhileLessThanMask32Bit(0, Size);
+                while (Sve.TestFirstTrue(pTrue, pLoop))
+                {
+                    // Load indices
+                    Vector<uint> idxVec = Sve.LoadVector(pLoop, indices + i);
+                    // Gather elements from objects using indices.
+                    Vector<uint> objVec = Sve.GatherVector(pLoop, objects, idxVec);
+                    // Add results to resVec.
+                    resVec = Sve.Add(resVec, objVec);
+
+                    i += cntw;
+                    pLoop = Sve.CreateWhileLessThanMask32Bit(i, Size);
+                }
+                // Add up all elements in resVec.
+                ulong res = (ulong)Sve.AddAcross(resVec).ToScalar();
+                _result = res;
+            }
+        }
+
+    }
+}

src/benchmarks/micro/sve/ScatterStore.cs

@@ -0,0 +1,98 @@
+using System;
+using System.Diagnostics;
+using System.Numerics;
+using System.Runtime.Intrinsics;
+using System.Runtime.Intrinsics.Arm;
+using BenchmarkDotNet.Attributes;
+using BenchmarkDotNet.Extensions;
+using BenchmarkDotNet.Configs;
+using BenchmarkDotNet.Filters;
+using MicroBenchmarks;
+
+namespace SveBenchmarks
+{
+    [BenchmarkCategory(Categories.Runtime)]
+    [OperatingSystemsArchitectureFilter(allowed: true, System.Runtime.InteropServices.Architecture.Arm64)]
+    [Config(typeof(Config))]
+    public class ScatterStore
+    {
+        private class Config : ManualConfig
+        {
+            public Config()
+            {
+                AddFilter(new SimpleFilter(_ => Sve.IsSupported));
+            }
+        }
+
+        [Params(15, 127, 527, 10015)]
+        public int Size;
+
+        private uint[] _objects;
+        private uint[] _indices;
+
+        [GlobalSetup]
+        public virtual void Setup()
+        {
+            _objects = new uint[Size];
+            _indices = ValuesGenerator.Array<uint>(Size);
+            for (int i = 0; i < Size; i++)
+            {
+                _indices[i] %= (uint)Size;
+            }
+        }
+
+        [GlobalCleanup]
+        public virtual void Verify()
+        {
+            uint[] current = (uint[])_objects.Clone();
+            Setup();
+            Scalar();
+            uint[] scalar = (uint[])_objects.Clone();
+            // Check that the result is the same as the scalar result.
+            for (int i = 0; i < current.Length; i++)
+            {
+                Debug.Assert(current[i] == scalar[i]);
+            }
+        }
+
+        // The following algorithms are adapted from the Arm simd-loops repository:
+        // https://gitlab.arm.com/architecture/simd-loops/-/blob/main/loops/loop_019.c
+
+        [Benchmark]
+        public unsafe void Scalar()
+        {
+            fixed (uint* objects = _objects, indices = _indices)
+            {
+                for (int i = 0; i < Size; i++)
+                {
+                    objects[indices[i]] = 1;
+                }
+            }
+        }
+
+        [Benchmark]
+        public unsafe void SveScatterStore()
+        {
+            fixed (uint* objects = _objects, indices = _indices)
+            {
+                int i = 0;
+                int cntw = (int)Sve.Count32BitElements();
+
+                Vector<uint> ones = Vector<uint>.One;
+                Vector<uint> pTrue = Sve.CreateTrueMaskUInt32();
+                Vector<uint> pLoop = Sve.CreateWhileLessThanMask32Bit(0, Size);
+                while (Sve.TestFirstTrue(pTrue, pLoop))
+                {
+                    Vector<uint> idxVec = Sve.LoadVector(pLoop, indices + i);
+
+                    // Set the indices within objects with ones.
+                    Sve.Scatter(pLoop, objects, idxVec, ones);
+
+                    i += cntw;
+                    pLoop = Sve.CreateWhileLessThanMask32Bit(i, Size);
+                }
+            }
+        }
+
+    }
+}