README.md

IntrinsicsPlayground

My toys to play with intrinsics in pure C# (see System.Runtime.Intrinsics.Experimental)

Environment:

BenchmarkDotNet=v0.10.14, OS=Windows 10.0.17134
Intel Core i7-8700K CPU 3.70GHz (Coffee Lake), 1 CPU, 12 logical and 6 physical cores
Frequency=3609374 Hz, Resolution=277.0564 ns, Timer=TSC
.NET Core SDK=2.1.301
  [Host]     : .NET Core 2.1.1 (CoreCLR 4.6.26606.02, CoreFX 4.6.26606.05), 64bit RyuJIT
  DefaultJob : .NET Core 2.1.1 (CoreCLR 4.6.26606.02, CoreFX 4.6.26606.05), 64bit RyuJIT

1. ArraySum

Sum of elements in an array of floats

var sum = arrayOfFloats.Sum();

Method	TestArrayLength	Mean	Scaled
Sum_LINQ	10	45.629 ns	4.81
Sum_Simple	10	2.879 ns	0.30
Sum_LinqFasterLib	10	15.100 ns	1.59
Sum_Avx	10	9.496 ns	1.00
Sum_LINQ	121	439.021 ns	25.20
Sum_Simple	121	78.111 ns	4.48
Sum_LinqFasterLib	121	22.432 ns	1.29
Sum_Avx	121	17.423 ns	1.00
Sum_LINQ	32768	109,128.390 ns	31.87
Sum_Simple	32768	27,345.722 ns	7.99
Sum_LinqFasterLib	32768	3,432.010 ns	1.00
Sum_Avx	32768	3,423.826 ns	1.00

2. ArrayEqual

Are arrays of floats equal?

var equal = arrayOfFloats1.SequenceEqual(arrayOfFloats2);

Method	TestArrayLength	Mean	Scaled
ArrayEqual_LINQ	10	116.175 ns	30.22
ArrayEqual_Simple	10	6.130 ns	1.59
ArrayEqual_AVX2	10	3.845 ns	1.00
ArrayEqual_LINQ	121	783.744 ns	50.82
ArrayEqual_Simple	121	60.981 ns	3.95
ArrayEqual_AVX2	121	15.425 ns	1.00
ArrayEqual_LINQ	32768	198,072.829 ns	52.85
ArrayEqual_Simple	32768	13,773.698 ns	3.67
ArrayEqual_AVX2	32768	3,748.025 ns	1.00

3. ArrayMax

Max element in an array of ints

var max = arrayOfInts.Max();

Method	TestArrayLength	Mean	Scaled
Max_LINQ	10	44.932 ns	3.38
Max_Simple	10	3.125 ns	0.23
Max_LinqFasterLib	10	14.071 ns	1.06
Max_Avx	10	13.307 ns	1.00
Max_LINQ	121	447.998 ns	23.34
Max_Simple	121	42.731 ns	2.23
Max_LinqFasterLib	121	19.230 ns	1.00
Max_Avx	121	19.219 ns	1.00
Max_LINQ	32768	116,163.414 ns	69.46
Max_Simple	32768	10,300.011 ns	6.16
Max_LinqFasterLib	32768	1,759.705 ns	1.05
Max_Avx	32768	1,672.383 ns	1.00

4. ArrayIsSorted

Check if an array is sorted or not

bool IsSorted(int[] array)
{
    if (array.Length < 2)
        return true;

    for (int i = 0; i < array.Length - 1; i++)
    {
        if (array[i] > array[i + 1])
            return false;
    }
    return true;
}

Method	TestArrayLength	Mean	Scaled
IsSorted_Simple	10	6.309 ns	2.51
IsSorted_Simple_Optimized	10	4.784 ns	1.90
IsSorted_Sse41	10	2.691 ns	1.07
IsSorted_Avx2	10	2.513 ns	1.00
IsSorted_Simple	121	80.036 ns	6.38
IsSorted_Simple_Optimized	121	54.508 ns	4.35
IsSorted_Sse41	121	22.927 ns	1.83
IsSorted_Avx2	121	12.539 ns	1.00
IsSorted_Simple	32768	19,928.318 ns	5.31
IsSorted_Simple_Optimized	32768	13,705.714 ns	3.65
IsSorted_Sse41	32768	6,190.854 ns	1.65
IsSorted_Avx2	32768	3,755.430 ns	1.00

5. ArrayReverse

Reverse all elements in an array

Array.Reverse(arrayOfInts);

Method	TestArrayLength	Mean	Scaled
Reverse_BCL	10	46.72 ns	0.96
Reverse_SSE	10	48.70 ns	1.00
Reverse_BCL	121	102.90 ns	1.27
Reverse_SSE	121	80.82 ns	1.00
Reverse_BCL	32768	18,083.44 ns	1.56
Reverse_SSE	32768	11,577.33 ns	1.00

6. ArrayIndexOf

Searche for the specified element and returns the index of its first occurrence

int index = Array.IndexOf(arrayOfInts, element);

Method	TestArrayLength	Mean	Scaled
IndexOf_BCL	10	7.701 ns	1.37
IndexOf_Avx2	10	5.620 ns	1.00
IndexOf_BCL	121	31.721 ns	3.59
IndexOf_Avx2	121	8.825 ns	1.00
IndexOf_BCL	32768	6,961.574 ns	3.72
IndexOf_Avx2	32768	1,870.329 ns	1.00

7. MatrixSum

Add two matrices (Matrix4x4)

var matrix3 = matrix1 + matrix2;

Method	Mean	Scaled
MatrixSum_BCL	25.81 us	1.30
MatrixSum_Avx	19.89 us	1.00

8. MatrixNegate

Negate a matrix (Matrix4x4)

matrix = -matrix;

Method	Mean	Scaled
MatrixNegate_BCL	34.31 us	1.38
MatrixNegate_Avx	24.87 us	1.00

9. MatrixMultiply

Multiply a matrix by a vector

matrix = matrix * vec;

Method	Mean	Scaled
MatrixMultiply_ByVector_BCL	28.01 us	1.04
MatrixMultiply_ByVector_Avx	26.83 us	1.00

Misc

1. Array.Sort vs DualPivotQuickSort

Dual pivot quick sort is used in Java for primitive types (Arrays.sort(int[])).