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 // Copyright 2020 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package test import "testing" // Benchmark multiplication of an integer by various constants. // // The comment above each sub-benchmark provides an example of how the // target multiplication operation might be implemented using shift // (multiplication by a power of 2), addition and subtraction // operations. It is platform-dependent whether these transformations // are actually applied. var ( mulSinkI32 int32 mulSinkI64 int64 mulSinkU32 uint32 mulSinkU64 uint64 ) func BenchmarkMulconstI32(b *testing.B) { // 3x = 2x + x b.Run("3", func(b *testing.B) { x := int32(1) for i := 0; i < b.N; i++ { x *= 3 } mulSinkI32 = x }) // 5x = 4x + x b.Run("5", func(b *testing.B) { x := int32(1) for i := 0; i < b.N; i++ { x *= 5 } mulSinkI32 = x }) // 12x = 8x + 4x b.Run("12", func(b *testing.B) { x := int32(1) for i := 0; i < b.N; i++ { x *= 12 } mulSinkI32 = x }) // 120x = 128x - 8x b.Run("120", func(b *testing.B) { x := int32(1) for i := 0; i < b.N; i++ { x *= 120 } mulSinkI32 = x }) // -120x = 8x - 120x b.Run("-120", func(b *testing.B) { x := int32(1) for i := 0; i < b.N; i++ { x *= -120 } mulSinkI32 = x }) // 65537x = 65536x + x b.Run("65537", func(b *testing.B) { x := int32(1) for i := 0; i < b.N; i++ { x *= 65537 } mulSinkI32 = x }) // 65538x = 65536x + 2x b.Run("65538", func(b *testing.B) { x := int32(1) for i := 0; i < b.N; i++ { x *= 65538 } mulSinkI32 = x }) } func BenchmarkMulconstI64(b *testing.B) { // 3x = 2x + x b.Run("3", func(b *testing.B) { x := int64(1) for i := 0; i < b.N; i++ { x *= 3 } mulSinkI64 = x }) // 5x = 4x + x b.Run("5", func(b *testing.B) { x := int64(1) for i := 0; i < b.N; i++ { x *= 5 } mulSinkI64 = x }) // 12x = 8x + 4x b.Run("12", func(b *testing.B) { x := int64(1) for i := 0; i < b.N; i++ { x *= 12 } mulSinkI64 = x }) // 120x = 128x - 8x b.Run("120", func(b *testing.B) { x := int64(1) for i := 0; i < b.N; i++ { x *= 120 } mulSinkI64 = x }) // -120x = 8x - 120x b.Run("-120", func(b *testing.B) { x := int64(1) for i := 0; i < b.N; i++ { x *= -120 } mulSinkI64 = x }) // 65537x = 65536x + x b.Run("65537", func(b *testing.B) { x := int64(1) for i := 0; i < b.N; i++ { x *= 65537 } mulSinkI64 = x }) // 65538x = 65536x + 2x b.Run("65538", func(b *testing.B) { x := int64(1) for i := 0; i < b.N; i++ { x *= 65538 } mulSinkI64 = x }) } func BenchmarkMulconstU32(b *testing.B) { // 3x = 2x + x b.Run("3", func(b *testing.B) { x := uint32(1) for i := 0; i < b.N; i++ { x *= 3 } mulSinkU32 = x }) // 5x = 4x + x b.Run("5", func(b *testing.B) { x := uint32(1) for i := 0; i < b.N; i++ { x *= 5 } mulSinkU32 = x }) // 12x = 8x + 4x b.Run("12", func(b *testing.B) { x := uint32(1) for i := 0; i < b.N; i++ { x *= 12 } mulSinkU32 = x }) // 120x = 128x - 8x b.Run("120", func(b *testing.B) { x := uint32(1) for i := 0; i < b.N; i++ { x *= 120 } mulSinkU32 = x }) // 65537x = 65536x + x b.Run("65537", func(b *testing.B) { x := uint32(1) for i := 0; i < b.N; i++ { x *= 65537 } mulSinkU32 = x }) // 65538x = 65536x + 2x b.Run("65538", func(b *testing.B) { x := uint32(1) for i := 0; i < b.N; i++ { x *= 65538 } mulSinkU32 = x }) } func BenchmarkMulconstU64(b *testing.B) { // 3x = 2x + x b.Run("3", func(b *testing.B) { x := uint64(1) for i := 0; i < b.N; i++ { x *= 3 } mulSinkU64 = x }) // 5x = 4x + x b.Run("5", func(b *testing.B) { x := uint64(1) for i := 0; i < b.N; i++ { x *= 5 } mulSinkU64 = x }) // 12x = 8x + 4x b.Run("12", func(b *testing.B) { x := uint64(1) for i := 0; i < b.N; i++ { x *= 12 } mulSinkU64 = x }) // 120x = 128x - 8x b.Run("120", func(b *testing.B) { x := uint64(1) for i := 0; i < b.N; i++ { x *= 120 } mulSinkU64 = x }) // 65537x = 65536x + x b.Run("65537", func(b *testing.B) { x := uint64(1) for i := 0; i < b.N; i++ { x *= 65537 } mulSinkU64 = x }) // 65538x = 65536x + 2x b.Run("65538", func(b *testing.B) { x := uint64(1) for i := 0; i < b.N; i++ { x *= 65538 } mulSinkU64 = x }) }