cgo-benchmark.go

package main

/*
	#include <sys/time.h>
	#include <pthread.h>

	static unsigned int
	plusOne(unsigned int x) {
		return x + 1;
	}

	static void
	benchmarkMutex(unsigned int iterations) {
		pthread_mutex_t m;
		pthread_mutex_init(&m, NULL);
		for (unsigned int i = 0; i < iterations; i++) {
			pthread_mutex_lock(&m);
			pthread_mutex_unlock(&m);
		}
	}

	static void
	benchmarkTime(unsigned int iterations) {
		for (unsigned int i = 0; i < iterations; i++) {
			struct timeval tv;
			gettimeofday(&tv, NULL);
		}
	}
*/
import "C"
import (
	"fmt"
	"os"
	"strconv"
	"sync"
	"time"
)

func plusOne(x uint) uint {
	return x + 1
}

func main() {
	var modifier uint
	var result uint
	var mutex sync.Mutex
	var iterations uint
	if len(os.Args) > 1 {
		i, _ := strconv.ParseUint(os.Args[1], 10, 32)
		iterations = uint(i)
		modifier = 1
	} else {
		iterations = 100000
		modifier = 2
	}

	a := time.Now()
	for i := uint(0); i < iterations; i++ {
		result += uint(C.plusOne(C.uint(i))) + modifier
	}
	b := time.Now()
	for i := uint(0); i < iterations; i++ {
		result += plusOne(i) + modifier
	}
	c := time.Now()
	for i := uint(0); i < iterations; i++ {
		mutex.Lock()
		mutex.Unlock()
	}
	d := time.Now()
	C.benchmarkMutex(C.uint(iterations))
	e := time.Now()
	C.benchmarkTime(C.uint(iterations))
	f := time.Now()

	fmt.Printf("CGo plusOne: %v ns/call\n", float64(b.Sub(a))/float64(iterations))
	fmt.Printf("Go  plusOne: %v ns/call\n", float64(c.Sub(b))/float64(iterations))
	fmt.Printf("Go  mutex  : %v ns/call\n", float64(d.Sub(c))/float64(iterations))
	fmt.Printf("C mutex    : %v ns/call\n", float64(e.Sub(d))/float64(iterations))
	fmt.Printf("C time     : %v ns/call\n", float64(f.Sub(e))/float64(iterations))
}