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avx reset #279

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cbf68a5
bench
Sep 28, 2022
9d11c50
Merge branch 'main' into users/alexpeck/resetavx
bitfaster Oct 1, 2022
98ea708
Merge branch 'main' into users/alexpeck/resetavx
Oct 8, 2022
384a7c9
Merge branch 'main' into users/alexpeck/resetavx
Oct 9, 2022
02e6fb9
align
Oct 9, 2022
a4e659a
cleanup
Oct 9, 2022
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3 changes: 2 additions & 1 deletion BitFaster.Caching.Benchmarks/BitFaster.Caching.Benchmarks.csproj
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Expand Up @@ -2,7 +2,8 @@

<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFrameworks>net48;net6.0</TargetFrameworks>
<TargetFrameworks>net6.0</TargetFrameworks>
<AllowUnsafeBlocks>True</AllowUnsafeBlocks>
</PropertyGroup>

<PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
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170 changes: 168 additions & 2 deletions BitFaster.Caching.Benchmarks/Lfu/SketchReset.cs
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Original file line number Diff line number Diff line change
@@ -1,6 +1,12 @@

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Jobs;
using BitFaster.Caching.Lfu;
using Microsoft.Diagnostics.Tracing.StackSources;
using System.Collections.Generic;
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.X86;


namespace BitFaster.Caching.Benchmarks.Lfu
{
Expand All @@ -12,11 +18,11 @@ public class SketchReset

long[] table;

[Params(4, 128, 8192, 1048576)]
[Params(8192, 1048576)]
public int Size { get; set; }

[GlobalSetup]
public void Setup()
public unsafe void Setup()
{
table = new long[Size];
}
Expand Down Expand Up @@ -75,5 +81,165 @@ public int Reset4()

return (count0 + count1) + (count2 + count3);
}

[Benchmark()]
public int Reset4NoPopcount()
{
for (int i = 0; i < table.Length; i += 4)
{
table[i] = (long)((ulong)table[i] >> 1) & ResetMask;
table[i + 1] = (long)((ulong)table[i + 1] >> 1) & ResetMask;
table[i + 2] = (long)((ulong)table[i + 2] >> 1) & ResetMask;
table[i + 3] = (long)((ulong)table[i + 3] >> 1) & ResetMask;
}

return 0;
}

[Benchmark()]
public unsafe int ResetAVXNoPopcount()
{
var resetMaskVector = Vector256.Create(ResetMask);

fixed (long* tPtr = table)
{
for (int i = 0; i < table.Length; i += 4)
{
Vector256<long> t = Avx2.LoadVector256(tPtr + i);
t = Avx2.ShiftRightLogical(t, 1);
t = Avx2.And(t, resetMaskVector);
Avx2.Store(tPtr + i, t);
}
}

return 0;
}

[Benchmark()]
public unsafe int ResetAVXNoPopcountUnroll2()
{
if (table.Length < 16)
{
return ResetAVXNoPopcount();
}

var resetMaskVector = Vector256.Create(ResetMask);

fixed (long* tPtr = table)
{
for (int i = 0; i < table.Length; i += 8)
{
Vector256<long> t1 = Avx2.LoadVector256(tPtr + i);
t1 = Avx2.ShiftRightLogical(t1, 1);
t1 = Avx2.And(t1, resetMaskVector);
Avx2.Store(tPtr + i, t1);

Vector256<long> t2 = Avx2.LoadVector256(tPtr + i + 4);
t2 = Avx2.ShiftRightLogical(t2, 1);
t2 = Avx2.And(t2, resetMaskVector);
Avx2.Store(tPtr + i + 4, t2);
}
}

return 0;
}

[Benchmark()]
public unsafe int ResetAVXNoPopcountUnroll4()
{
if (table.Length < 16)
{
return ResetAVXNoPopcount();
}

var resetMaskVector = Vector256.Create(ResetMask);

fixed (long* tPtr = table)
{
for (int i = 0; i < table.Length; i += 16)
{
Vector256<long> t1 = Avx2.LoadVector256(tPtr + i);
t1 = Avx2.ShiftRightLogical(t1, 1);
t1 = Avx2.And(t1, resetMaskVector);
Avx2.Store(tPtr + i, t1);

Vector256<long> t2 = Avx2.LoadVector256(tPtr + i + 4);
t2 = Avx2.ShiftRightLogical(t2, 1);
t2 = Avx2.And(t2, resetMaskVector);
Avx2.Store(tPtr + i + 4, t2);

Vector256<long> t3 = Avx2.LoadVector256(tPtr + i + 8);
t3 = Avx2.ShiftRightLogical(t3, 1);
t3 = Avx2.And(t3, resetMaskVector);
Avx2.Store(tPtr + i + 8, t3);

Vector256<long> t4 = Avx2.LoadVector256(tPtr + i + 12);
t4 = Avx2.ShiftRightLogical(t4, 1);
t4 = Avx2.And(t4, resetMaskVector);
Avx2.Store(tPtr + i + 12, t4);
}
}

return 0;
}

[Benchmark()]
public unsafe int ResetAVXAlignedNoPopcountUnroll4()
{
if (table.Length < 16)
{
return ResetAVXNoPopcount();
}

var resetMaskVector = Vector256.Create(ResetMask);

fixed (long* tPtr = table)
{
long* alignedPtr = tPtr;
int remainder = 0;

while (((ulong)alignedPtr & 31UL) != 0)
{
*alignedPtr = (*alignedPtr >> 1) & ResetMask;
alignedPtr++;
remainder = 16;
}

int c = table.Length - (int)(alignedPtr - tPtr) - remainder;
int i = 0;

for(; i < c; i += 16)
{
Vector256<long> t1 = Avx2.LoadAlignedVector256(alignedPtr + i);
Vector256<long> t2 = Avx2.LoadAlignedVector256(alignedPtr + i + 4);
Vector256<long> t3 = Avx2.LoadAlignedVector256(alignedPtr + i + 8);
Vector256<long> t4 = Avx2.LoadAlignedVector256(alignedPtr + i + 12);

t1 = Avx2.ShiftRightLogical(t1, 1);
t2 = Avx2.ShiftRightLogical(t2, 1);
t3 = Avx2.ShiftRightLogical(t3, 1);
t4 = Avx2.ShiftRightLogical(t4, 1);

t1 = Avx2.And(t1, resetMaskVector);
t2 = Avx2.And(t2, resetMaskVector);
t3 = Avx2.And(t3, resetMaskVector);
t4 = Avx2.And(t4, resetMaskVector);

Avx2.StoreAligned(alignedPtr + i, t1);
Avx2.StoreAligned(alignedPtr + i + 4, t2);
Avx2.StoreAligned(alignedPtr + i + 8, t3);
Avx2.StoreAligned(alignedPtr + i + 12, t4);
}

int start = (int)(alignedPtr - tPtr) + i;

for (int j = start; j < table.Length; j++)
{
tPtr[j] = (tPtr[j] >> 1) & ResetMask;
}

return 0;
}
}
}
}
95 changes: 95 additions & 0 deletions BitFaster.Caching.UnitTests/Alignment.cs
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@@ -0,0 +1,95 @@
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Runtime.Intrinsics.X86;
using System.Runtime.Intrinsics;
using System.Text;
using System.Threading.Tasks;
using Xunit;
using FluentAssertions;

namespace BitFaster.Caching.UnitTests
{
public class Alignment
{
static long ResetMask = 0x7777777777777777L;

long[] table;

private const ulong AlignmentMask = 31UL;

[Fact]
public void Runner()
{
for (int i = 0; i < 8000; i++)
{
Test();
}
}

private unsafe void Test()
{
table = new long[128];

for (int i = 0; i < table.Length; i++)
{
table[i] = 15;
}


var resetMaskVector = Vector256.Create(ResetMask);

fixed (long* tPtr = table)
{
long* alignedPtr = tPtr;
int remainder = 0;

while (((ulong)alignedPtr & 31UL) != 0)
{
*alignedPtr = (*alignedPtr >> 1) & ResetMask;
alignedPtr++;
remainder = 16;
}

int c = table.Length - (int)(alignedPtr - tPtr) - remainder;
int i = 0;

for (; i < c; i += 16)
{
Vector256<long> t1 = Avx2.LoadAlignedVector256(alignedPtr + i);
t1 = Avx2.ShiftRightLogical(t1, 1);
t1 = Avx2.And(t1, resetMaskVector);
Avx2.StoreAligned(alignedPtr + i, t1);

Vector256<long> t2 = Avx2.LoadAlignedVector256(alignedPtr + i + 4);
t2 = Avx2.ShiftRightLogical(t2, 1);
t2 = Avx2.And(t2, resetMaskVector);
Avx2.StoreAligned(alignedPtr + i + 4, t2);

Vector256<long> t3 = Avx2.LoadAlignedVector256(alignedPtr + i + 8);
t3 = Avx2.ShiftRightLogical(t3, 1);
t3 = Avx2.And(t3, resetMaskVector);
Avx2.StoreAligned(alignedPtr + i + 8, t3);

Vector256<long> t4 = Avx2.LoadAlignedVector256(alignedPtr + i + 12);
t4 = Avx2.ShiftRightLogical(t4, 1);
t4 = Avx2.And(t4, resetMaskVector);
Avx2.StoreAligned(alignedPtr + i + 12, t4);
}

int start = (int)(alignedPtr - tPtr) + i;

for (int j = start; j < table.Length; j++)
{
tPtr[j] = (tPtr[j] >> 1) & ResetMask;
}

for (int j = 0; j < table.Length; j++)
{
table[j].Should().Be(7);
}
}
}
}
}
1 change: 1 addition & 0 deletions BitFaster.Caching.UnitTests/BitFaster.Caching.UnitTests.csproj
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@

<PropertyGroup>
<TargetFramework>net6.0</TargetFramework>
<AllowUnsafeBlocks>True</AllowUnsafeBlocks>
</PropertyGroup>

<ItemGroup>
Expand Down