我无法获得真正的事件循环阻塞时间。我搜索了谷歌的答案(here),但他们对我没有帮助。我得到了不同的结果。
我创建了Node / Express应用程序。并尝试使用不同的工具检测事件循环阻塞。我用过hrtime,pm2,blocked_at。
1测试:
server.js
require('./routes')(app, passport, mongoData)
路线/ index.js
router
.get('/articles/:articleId(\\d+)', (req, res, next) => {
const blockedAt = require('blocked-at')
blockedAt((time, stack) => {
console.log(`Blocked for ${time}ms, operation started here:`, stack)
}, {threshold:12})
// my blocking script
for (let i = 0; i <= 1000000000; i++) {
let z = 10000 / Math.random()
}
let ArticleController = require(path + 'app/controllers/ArticleController')
let articleController = new ArticleController()
articleController.index(req, res, next)
})
我有:
阻止15.5994921875ms,操作从这里开始:['at','在ArticleService.getArticle(/app/services/article/ArticleService.js:79:44)']被阻止为14.0350537109375ms,操作从这里开始:['在Promise ExpressHandlebars上的.then()','在ExpressHandlebars.render(node_modules / express-handlebars / lib / express-handlebars.js:157:8)','。 (node_modules / express-handlebars / lib / express-handlebars.js:226:29)']
但没有关于我的阻止脚本!
2测试:
用pm2:
删除我的阻止脚本后,我得到相同的结果。
3测试:
使用hrtime我在ArticleController.index中测量。索引方法以异步模式加载3个服务。有很多I / O操作,并且工作有worker_threads。一些代码创建到setImmediate中。
进入索引:
let hrstart = process.hrtime()
// there works all my services
//...
let hrend = process.hrtime(hrstart)
console.info('Execution time (hr): %ds ir ms: %dms', hrend[0], hrend[1] / 1000000)
res.render('home', data)
我有1s,233ms。我很开心,但我很困惑 - 因为所有操作都在异步模式下工作,事件循环没有阻塞?
我如何测量事件循环块?
我期望输出:“在routes / index.js中阻止事件循环:12秒为5000毫秒”,但实际输出没有捕获我的阻塞脚本。
阻止事件循环的时间量是您按顺序处理的时间。您的示例将是该函数的主体。所以你可以只计算时间并将其添加到变量中。
let totalBlocked = 0;
router
.get('/articles/:articleId(\\d+)', (req, res, next) => {
const start = new Date().getTime();
// my blocking script
for (let i = 0; i <= 1000000000; i++) {
let z = 10000 / Math.random() ;
}
let ArticleController = require(path + 'app/controllers/ArticleController');
let articleController = new ArticleController();
articleController.index(req, res, next);
const total = new Date().getTime() - start;
totalBlocked += total;
console.log(`Blocked for ${total}. Total blocked time is ${totalBlocked}`);
});
您还可以使用Node perf_hooks
进行高分辨率计时。
const {performance } = require('perf_hooks');
let totalBlocked = 0;
router
.get('/articles/:articleId(\\d+)', (req, res, next) => {
const start = performance.now();
// Do stuff
const total = performance.now() - start;
totalBlocked += total;
console.log(`Blocked for ${total}. Total blocked time is ${totalBlocked}`);
});