routine_bench.go

package internal

import (
	"sync"
	"testing"
	"time"
)

//goos: darwin
//goarch: amd64
//pkg: hello/internal
//cpu: Intel(R) Core(TM) i9-9980HK CPU @ 2.40GHz
//BenchmarkSpawnInWild
//BenchmarkSpawnInWild-16    	       1	2477192780 ns/op	 4712624 B/op	   25819 allocs/op
//BenchmarkWorkerPool
//BenchmarkWorkerPool-16     	       1	2546894379 ns/op	  257424 B/op	    9022 allocs/op

const (
	numComputeUnit    = 32
	rangeLimit        = 10_000
	concurrentCompute = 256
)

func BenchmarkSpawnInWild(b *testing.B) {
	b.ReportAllocs()
	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		var wg sync.WaitGroup
		wg.Add(concurrentCompute)
		for j := 0; j < concurrentCompute; j++ {
			go func() {
				computeWithWildRoutines()
				wg.Done()
			}()
		}
		wg.Wait()
	}
}

func BenchmarkWorkerPool(b *testing.B) {
	// start worker pool
	taskCh := make(chan func(), 64)
	for i := 0; i < 128; i++ {
		go func() {
			for task := range taskCh {
				task() // execute task
			}
		}()
	}

	b.ReportAllocs()
	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		var wg sync.WaitGroup
		wg.Add(concurrentCompute)
		for j := 0; j < concurrentCompute; j++ {
			go func() {
				computeWithWorkerPool(taskCh)
				wg.Done()
			}()
		}
		wg.Wait()
	}

	close(taskCh)
}

func computeWithWildRoutines() {
	out := make(chan int, numComputeUnit)

	for i := 0; i < numComputeUnit; i++ {
		go func() {
			total := 0
			for i := 1; i <= rangeLimit; i++ {
				total += i%593 + (i*i)/913
				time.Sleep(time.Microsecond)
			}
			out <- total
		}()
	}

	sum := 0
	for i := 0; i < numComputeUnit; i++ {
		sum += <-out
	}

	if sum == 0 {
		panic(sum)
	}
}

func computeWithWorkerPool(taskCh chan func()) {
	out := make(chan int, numComputeUnit)

	for i := 0; i < numComputeUnit; i++ {
		// give compute task to allocated workers
		taskCh <- func() {
			total := 0
			for i := 1; i <= rangeLimit; i++ {
				total += i%593 + (i*i)/913
				time.Sleep(time.Microsecond)
			}
			out <- total
		}
	}

	sum := 0
	for i := 0; i < numComputeUnit; i++ {
		sum += <-out
	}

	if sum == 0 {
		panic(sum)
	}
}