runtime_sema_test.go

Documentation: sync

		 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, 0)
		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, 0)
		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, 0)
		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
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