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) 22 Runtime_Semacquire(&sem.sem) 23 } 24 }) 25 } 26 27 func benchmarkSema(b *testing.B, block, work bool) { 28 sem := uint32(0) 29 if block { 30 done := make(chan bool) 31 go func() { 32 for p := 0; p < runtime.GOMAXPROCS(0)/2; p++ { 33 Runtime_Semacquire(&sem) 34 } 35 done <- true 36 }() 37 defer func() { 38 <-done 39 }() 40 } 41 b.RunParallel(func(pb *testing.PB) { 42 foo := 0 43 for pb.Next() { 44 Runtime_Semrelease(&sem) 45 if work { 46 for i := 0; i < 100; i++ { 47 foo *= 2 48 foo /= 2 49 } 50 } 51 Runtime_Semacquire(&sem) 52 } 53 _ = foo 54 Runtime_Semrelease(&sem) 55 }) 56 } 57 58 func BenchmarkSemaSyntNonblock(b *testing.B) { 59 benchmarkSema(b, false, false) 60 } 61 62 func BenchmarkSemaSyntBlock(b *testing.B) { 63 benchmarkSema(b, true, false) 64 } 65 66 func BenchmarkSemaWorkNonblock(b *testing.B) { 67 benchmarkSema(b, false, true) 68 } 69 70 func BenchmarkSemaWorkBlock(b *testing.B) { 71 benchmarkSema(b, true, true) 72 } 73
