func_bench

gistfile1.go

package functest

import "testing"
import "runtime"

type Target struct {
	in chan TestFunc
	state int
}

func (t *Target)DoSomething(param int) {
	t.state *= param
}

type TestFunc func(t *Target)

func MyFunc(t *Target) {
	t.DoSomething(42)
}

func BenchmarkDirectFunc(b *testing.B) {
	t := Target{}

	runtime.GOMAXPROCS(runtime.NumCPU())

	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		t.DoSomething(42)
	}
}

func BenchmarkChannelDontWait(b *testing.B) {
	t := Target{make(chan TestFunc),0}
	go func() {
		for {
			a := <-t.in
			a(&t)
		}
	}()

	runtime.GOMAXPROCS(runtime.NumCPU())

	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		t.in <- MyFunc
	}
}

func BenchmarkChannelWait(b *testing.B) {
	res := make(chan bool)
	t := Target{make(chan TestFunc),0}
	go func() {
		for {
			a := <-t.in
			a(&t)
			res<- true
		}
	}()

	runtime.GOMAXPROCS(runtime.NumCPU())

	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		t.in <- MyFunc
		<-res
	}
}

on x86 WinXP, 4 core CPU:

P:\updates\test>go test -file func_test.go -bench=.*
testing: warning: no tests to run
PASS
BenchmarkDirectFunc 500000000 3.44 ns/op
testing: BenchmarkDirectFunc left GOMAXPROCS set to 4
BenchmarkChannelDontWait 200000 8593 ns/op
testing: BenchmarkChannelDontWait left GOMAXPROCS set to 4
BenchmarkChannelWait 200000 17031 ns/op
testing: BenchmarkChannelWait left GOMAXPROCS set to 4
ok /P/updates/test 7.485s