Benchmarking make vs new for slice in golang (https://dev.to/freakynit/using-new-instead-of-make-to-create-slice-17bl)

benchmark.go

package main

import (
	"fmt"
	"time"
)

func testMakeSlice(numIterations int, numRuns int){
	a := make([]int32, 0)
	for k := 0; k < numRuns; k++ {
		for i := 0; i < numIterations; i++ {
			a = append(a, 10, 20, 30)
		}
	}
}

func testNewSlice(numIterations int, numRuns int){
	a := new([]int32)
	for k := 0; k < numRuns; k++ {
		for i := 0; i < numIterations; i++ {
			*a = append(*a, 10, 20, 30)
		}
	}
}

func testNewDereferencedSlice(numIterations int, numRuns int){
	a := *new([]int32)
	for k := 0; k < numRuns; k++ {
		for i := 0; i < numIterations; i++ {
			a = append(a, 10, 20, 30)
		}
	}
}

func benchmark(name string, f func(int, int), numIterations int, numRuns int){
	start := time.Now()
	f(numIterations, numRuns)
	fmt.Println(name, time.Now().Sub(start).Milliseconds()/int64(numRuns), "ms")
}

func warmup(numIterations int, numRuns int){
	var s int = 0
	for k := 0; k < numRuns; k++ {
		for i := 0; i < numIterations; i++ {
			s = s + i / 1000
		}
	}
}

func main() {
	var numIterations = 10_000_000
	var numRuns = 5

	for i := 0; i < 10; i++ {
		fmt.Println("===")
		benchmark("warmup", warmup, numIterations, numRuns)
		benchmark("testMakeSlice", testMakeSlice, numIterations, numRuns)
		benchmark("testNewSlice", testNewSlice, numIterations, numRuns)
		benchmark("testNewDereferencedSlice", testNewDereferencedSlice, numIterations, numRuns)
	}
}

Result

===
warmup 5 ms
testMakeSlice 241 ms
testNewSlice 116 ms
testNewDereferencedSlice 55 ms
===
warmup 3 ms
testMakeSlice 50 ms
testNewSlice 55 ms
testNewDereferencedSlice 50 ms
===
warmup 3 ms
testMakeSlice 96 ms
testNewSlice 55 ms
testNewDereferencedSlice 48 ms
===
warmup 3 ms
testMakeSlice 83 ms
testNewSlice 55 ms
testNewDereferencedSlice 48 ms
===
warmup 3 ms
testMakeSlice 49 ms
testNewSlice 55 ms
testNewDereferencedSlice 48 ms
===
warmup 3 ms
testMakeSlice 49 ms
testNewSlice 55 ms
testNewDereferencedSlice 48 ms
===
warmup 3 ms
testMakeSlice 55 ms
testNewSlice 55 ms
testNewDereferencedSlice 48 ms
===
warmup 3 ms
testMakeSlice 49 ms
testNewSlice 54 ms
testNewDereferencedSlice 48 ms
===
warmup 3 ms
testMakeSlice 48 ms
testNewSlice 55 ms
testNewDereferencedSlice 47 ms
===
warmup 3 ms
testMakeSlice 49 ms
testNewSlice 56 ms
testNewDereferencedSlice 48 ms