callback 和 promise 性能差距疑问

callback

import * as fs from 'fs';
import * as path from 'path';
function list_dir(dir: string) {
    fs.readdir(dir, 'utf-8', (err, files) => {
        files.forEach(file => {
            file = path.join(dir, file)
            fs.stat(file, (err, stat) => {
                if (stat.isDirectory()) {
                    list_dir(file)
                }
                if (stat.isFile()) {
                    file
                    // console.log("%O", file);
                }
            })
        });
    })
}

list_dir('.')

promise

import * as util from 'util';
import * as fs from 'fs';
import * as path from 'path';
async function list_dir(dir: string) {
    const readdir = util.promisify(fs.readdir);
    const stat = util.promisify(fs.stat);
    const files = await readdir(dir, 'utf-8')
    files.forEach(async file => {
        file = path.join(dir, file)
        const state = await stat(file)
        if (state.isDirectory()) {
            await list_dir(file)
        }
        if (state.isFile()) {
            file
            // console.log("%O", file);
        }
    })

}

list_dir('.')

性能测试结果

node ➜ /workspaces/typescript $ time node promise.js && time node callback.js

real    0m1.140s
user    0m1.136s
sys     0m1.292s

real    0m0.377s
user    0m0.368s
sys     0m0.534s
node ➜ /workspaces/typescript $ time node promise.js && time node callback.js

real    0m1.062s
user    0m1.132s
sys     0m1.184s

real    0m0.538s
user    0m0.470s
sys     0m0.784s
node ➜ /workspaces/typescript $ time node promise.js && time node callback.js

real    0m1.194s
user    0m1.221s
sys     0m1.308s

real    0m0.436s
user    0m0.393s
sys     0m0.651s
node ➜ /workspaces/typescript $ time node promise.js && time node callback.js

real    0m1.024s
user    0m1.165s
sys     0m1.027s

real    0m0.416s
user    0m0.313s
sys     0m0.653s
node ➜ /workspaces/typescript $ nodejs --version
v16.3.0
node ➜ /workspaces/typescript $ tsc --version
Version 4.3.5

有性能差异可以理解，但是这个性能差异过大，请问各位是我的写法有问题，还是其它原因导致的呢？