利用Grinder对使用await的web服务做负载测试，并以只使用callback的web服务作为对照.

• 测试环境： Linux Centos虚拟机 单核
• 测试参数:
  • grinder.processes=7
  • grinder.thread = 3
  • grinder.runs=600
     
• 测试结果：callback和await在并发性能上并无显著差异

• 	callback	await
  平均响应时间毫秒	34.8	34.4
  平均TPS	519	568
  峰值TPS	637	685
  CPU峰值	23%	23%
  测试总次数	12600	12600

源码如下:

server-with-callback.js

(function() {
  var http, sleep;

  http = require('http');

  sleep = function(callback) {
    return setTimeout(function() {
      return callback('wakeup');
    }, 30);
  };

  http.createServer(function(req, res) {
    sleep(function(msg){
       res.end(msg);
    });
  }).listen(8080);

}).call(this);

server-with-await.js

(function() {
  var aaa, http, sleep, wrapper;

  http = require('http');

  sleep = function(callback) {
    return setTimeout(function() {
      return callback('wakeup');
    }, 30);
  };

  http.createServer(async function(req, res) {
      var msg = await new Promise(function(resolve, reject){
          sleep(function(msg) {
             resolve(msg);
          });
      });
      res.end(msg);
  }).listen(8080);

}).call(this);