benchmark_chan.go

package hello

import (
	"testing"
	"sync"
)

func benchmarkChannel(b *testing.B, nProducer int) {
	ch := make(chan int)
	var wg sync.WaitGroup
	wg.Add(nProducer)

	//producer
	for i := 0; i < nProducer; i++ {
		go func() {
			for j := 0; j < b.N; j++ {
				ch <- 1
			}
			wg.Done();
		}()
	}

	//close signal handler
	go func() {
		wg.Wait();
		close(ch);
	}()

	//consumer
	var acc int = 0
	for data := range ch {
		acc += data
	}

}

func BenchmarkChannel1(b *testing.B) {
	benchmarkChannel(b, 1)
}

func BenchmarkChannel2(b *testing.B) {
	benchmarkChannel(b, 2)
}

func BenchmarkChannel4(b *testing.B) {
	benchmarkChannel(b, 4)
}

func BenchmarkChannel8(b *testing.B) {
	benchmarkChannel(b, 8)
}

func BenchmarkChannel16(b *testing.B) {
	benchmarkChannel(b, 16)
}

BenchmarkChannel1-8      5000000               242 ns/op            effective: 242 ns/op
BenchmarkChannel2-8      3000000               588 ns/op           effective: 294 ns/op
BenchmarkChannel4-8      1000000              1617 ns/op            effective: 404 ns/op
BenchmarkChannel8-8       300000              4125 ns/op            effective: 515 ns/op
BenchmarkChannel16-8      200000              9337 ns/op           effective: 583 ns/op

change ch := make(chan int) to ch := make(chan int,1024)

BenchmarkChannel1-8     20000000                92.4 ns/op
BenchmarkChannel2-8     10000000               209 ns/op
BenchmarkChannel4-8      3000000               546 ns/op
BenchmarkChannel8-8      1000000              1883 ns/op
BenchmarkChannel16-8      300000              3487 ns/op