1 // Copyright 2009 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 sync_test 6 7 import ( 8 "runtime" 9 . "sync" 10 "testing" 11 ) 12 13 func BenchmarkSemaUncontended(b *testing.B) { 14 type PaddedSem struct { 15 sem uint32 16 pad [32]uint32 17 } 18 b.RunParallel(func(pb *testing.PB) { 19 sem := new(PaddedSem) 20 for pb.Next() { 21 Runtime_Semrelease(&sem.sem, false) 22 Runtime_Semacquire(&sem.sem) 23 } 24 }) 25 } 26 27 func benchmarkSema(b *testing.B, block, work bool) { 28 if b.N == 0 { 29 return 30 } 31 sem := uint32(0) 32 if block { 33 done := make(chan bool) 34 go func() { 35 for p := 0; p < runtime.GOMAXPROCS(0)/2; p++ { 36 Runtime_Semacquire(&sem) 37 } 38 done <- true 39 }() 40 defer func() { 41 <-done 42 }() 43 } 44 b.RunParallel(func(pb *testing.PB) { 45 foo := 0 46 for pb.Next() { 47 Runtime_Semrelease(&sem, false) 48 if work { 49 for i := 0; i < 100; i++ { 50 foo *= 2 51 foo /= 2 52 } 53 } 54 Runtime_Semacquire(&sem) 55 } 56 _ = foo 57 Runtime_Semrelease(&sem, false) 58 }) 59 } 60 61 func BenchmarkSemaSyntNonblock(b *testing.B) { 62 benchmarkSema(b, false, false) 63 } 64 65 func BenchmarkSemaSyntBlock(b *testing.B) { 66 benchmarkSema(b, true, false) 67 } 68 69 func BenchmarkSemaWorkNonblock(b *testing.B) { 70 benchmarkSema(b, false, true) 71 } 72 73 func BenchmarkSemaWorkBlock(b *testing.B) { 74 benchmarkSema(b, true, true) 75 } 76
