1 // Copyright 2012 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package runtime_test 6 7 import ( 8 "runtime" 9 "testing" 10 ) 11 12 // arm soft division benchmarks adapted from 13 // http://ridiculousfish.com/files/division_benchmarks.tar.gz 14 15 const numeratorsSize = 1 << 21 16 17 var numerators = randomNumerators() 18 19 type randstate struct { 20 hi, lo uint32 21 } 22 23 func (r *randstate) rand() uint32 { 24 r.hi = r.hi<<16 + r.hi>>16 25 r.hi += r.lo 26 r.lo += r.hi 27 return r.hi 28 } 29 30 func randomNumerators() []uint32 { 31 numerators := make([]uint32, numeratorsSize) 32 random := &randstate{2147483563, 2147483563 ^ 0x49616E42} 33 for i := range numerators { 34 numerators[i] = random.rand() 35 } 36 return numerators 37 } 38 39 func bmUint32Div(divisor uint32, b *testing.B) { 40 var sum uint32 41 for i := 0; i < b.N; i++ { 42 sum += numerators[i&(numeratorsSize-1)] / divisor 43 } 44 } 45 46 func BenchmarkUint32Div7(b *testing.B) { bmUint32Div(7, b) } 47 func BenchmarkUint32Div37(b *testing.B) { bmUint32Div(37, b) } 48 func BenchmarkUint32Div123(b *testing.B) { bmUint32Div(123, b) } 49 func BenchmarkUint32Div763(b *testing.B) { bmUint32Div(763, b) } 50 func BenchmarkUint32Div1247(b *testing.B) { bmUint32Div(1247, b) } 51 func BenchmarkUint32Div9305(b *testing.B) { bmUint32Div(9305, b) } 52 func BenchmarkUint32Div13307(b *testing.B) { bmUint32Div(13307, b) } 53 func BenchmarkUint32Div52513(b *testing.B) { bmUint32Div(52513, b) } 54 func BenchmarkUint32Div60978747(b *testing.B) { bmUint32Div(60978747, b) } 55 func BenchmarkUint32Div106956295(b *testing.B) { bmUint32Div(106956295, b) } 56 57 func bmUint32Mod(divisor uint32, b *testing.B) { 58 var sum uint32 59 for i := 0; i < b.N; i++ { 60 sum += numerators[i&(numeratorsSize-1)] % divisor 61 } 62 } 63 64 func BenchmarkUint32Mod7(b *testing.B) { bmUint32Mod(7, b) } 65 func BenchmarkUint32Mod37(b *testing.B) { bmUint32Mod(37, b) } 66 func BenchmarkUint32Mod123(b *testing.B) { bmUint32Mod(123, b) } 67 func BenchmarkUint32Mod763(b *testing.B) { bmUint32Mod(763, b) } 68 func BenchmarkUint32Mod1247(b *testing.B) { bmUint32Mod(1247, b) } 69 func BenchmarkUint32Mod9305(b *testing.B) { bmUint32Mod(9305, b) } 70 func BenchmarkUint32Mod13307(b *testing.B) { bmUint32Mod(13307, b) } 71 func BenchmarkUint32Mod52513(b *testing.B) { bmUint32Mod(52513, b) } 72 func BenchmarkUint32Mod60978747(b *testing.B) { bmUint32Mod(60978747, b) } 73 func BenchmarkUint32Mod106956295(b *testing.B) { bmUint32Mod(106956295, b) } 74 75 func TestUsplit(t *testing.T) { 76 var den uint32 = 1000000 77 for _, x := range []uint32{0, 1, 999999, 1000000, 1010101, 0xFFFFFFFF} { 78 q1, r1 := runtime.Usplit(x) 79 q2, r2 := x/den, x%den 80 if q1 != q2 || r1 != r2 { 81 t.Errorf("%d/1e6, %d%%1e6 = %d, %d, want %d, %d", x, x, q1, r1, q2, r2) 82 } 83 } 84 } 85
