我有一段JavaScript代码,我正在使用node.js解释器执行。

for(var i = 1; i < LIMIT; i++) {
  var user = {
    id: i,
    name: "MongoUser [" + i + "]"
  };
  db.users.save(user, function(err, saved) {
    if(err || !saved) {
      console.log("Error");
    } else {
      console.log("Saved");
    }
  });
}

如何测量这些数据库插入操作所花费的时间?我可以在这段代码之后和之前计算日期值的差异,但这将是不正确的,因为代码的异步性质。


当前回答

你也可以试试exectimer。它会给你这样的反馈:

var t = require("exectimer");

var myFunction() {
   var tick = new t.tick("myFunction");
   tick.start();
   // do some processing and end this tick
   tick.stop();
}

// Display the results
console.log(t.timers.myFunction.duration()); // total duration of all ticks
console.log(t.timers.myFunction.min()); // minimal tick duration
console.log(t.timers.myFunction.max()); // maximal tick duration
console.log(t.timers.myFunction.mean()); // mean tick duration
console.log(t.timers.myFunction.median()); // median tick duration

现在有一种更简单的方法来使用exectime。你的代码可以这样包装:

var t = require('exectimer'),
Tick = t.Tick;

for(var i = 1; i < LIMIT; i++){
    Tick.wrap(function saveUsers(done) {
        db.users.save({id : i, name : "MongoUser [" + i + "]"}, function(err, saved) {
            if( err || !saved ) console.log("Error");
            else console.log("Saved");
            done();
        });
    });
}

// Display the results
console.log(t.timers.myFunction.duration()); // total duration of all ticks
console.log(t.timers.saveUsers.min()); // minimal tick duration
console.log(t.timers.saveUsers.max()); // maximal tick duration
console.log(t.timers.saveUsers.mean()); // mean tick duration
console.log(t.timers.saveUsers.median()); // median tick duration

其他回答

你也可以试试exectimer。它会给你这样的反馈:

var t = require("exectimer");

var myFunction() {
   var tick = new t.tick("myFunction");
   tick.start();
   // do some processing and end this tick
   tick.stop();
}

// Display the results
console.log(t.timers.myFunction.duration()); // total duration of all ticks
console.log(t.timers.myFunction.min()); // minimal tick duration
console.log(t.timers.myFunction.max()); // maximal tick duration
console.log(t.timers.myFunction.mean()); // mean tick duration
console.log(t.timers.myFunction.median()); // median tick duration

现在有一种更简单的方法来使用exectime。你的代码可以这样包装:

var t = require('exectimer'),
Tick = t.Tick;

for(var i = 1; i < LIMIT; i++){
    Tick.wrap(function saveUsers(done) {
        db.users.save({id : i, name : "MongoUser [" + i + "]"}, function(err, saved) {
            if( err || !saved ) console.log("Error");
            else console.log("Saved");
            done();
        });
    });
}

// Display the results
console.log(t.timers.myFunction.duration()); // total duration of all ticks
console.log(t.timers.saveUsers.min()); // minimal tick duration
console.log(t.timers.saveUsers.max()); // maximal tick duration
console.log(t.timers.saveUsers.mean()); // mean tick duration
console.log(t.timers.saveUsers.median()); // median tick duration

我从AWS转到Azure时也遇到了同样的问题

对于express和aws,您已经可以使用,existing time()和timeEnd()

对于Azure,使用这个: https://github.com/manoharreddyporeddy/my-nodejs-notes/blob/master/performance_timers_helper_nodejs_azure_aws.js

这些time()和timeEnd()使用现有的hrtime()函数,提供高分辨率的实时时间。

希望这能有所帮助。

有一种方法是专门为这个设计的。签出process.hrtime();.

我基本上把这个放在应用的顶部。

var start = process.hrtime();

var elapsed_time = function(note){
    var precision = 3; // 3 decimal places
    var elapsed = process.hrtime(start)[1] / 1000000; // divide by a million to get nano to milli
    console.log(process.hrtime(start)[0] + " s, " + elapsed.toFixed(precision) + " ms - " + note); // print message + time
    start = process.hrtime(); // reset the timer
}

然后我用它来看看函数需要多长时间。下面是一个基本的例子,打印一个名为"output.txt"的文本文件的内容:

var debug = true;
http.createServer(function(request, response) {

    if(debug) console.log("----------------------------------");
    if(debug) elapsed_time("recieved request");

    var send_html = function(err, contents) {
        if(debug) elapsed_time("start send_html()");
        response.writeHead(200, {'Content-Type': 'text/html' } );
        response.end(contents);
        if(debug) elapsed_time("end send_html()");
    }

    if(debug) elapsed_time("start readFile()");
    fs.readFile('output.txt', send_html);
    if(debug) elapsed_time("end readFile()");

}).listen(8080);

下面是一个可以在终端(BASH shell)中运行的快速测试:

for i in {1..100}; do echo $i; curl http://localhost:8080/; done

调用console.time('label')将以毫秒为单位记录当前时间,然后调用console.timeEnd('label')将显示从该点开始的持续时间。

以毫秒为单位的时间会自动打印在标签旁边,所以你不需要单独调用console.log来打印标签:

console.time('test');
//some code
console.timeEnd('test'); //Prints something like that-> test: 11374.004ms

有关更多信息,请参阅console.time上的Mozilla开发者文档。

令人惊讶的是,还没有人提到图书馆的新建:

在节点>= 8.5中可用,并且应该在现代浏览器中

https://developer.mozilla.org/en-US/docs/Web/API/Performance

https://nodejs.org/docs/latest-v8.x/api/perf_hooks.html#

节点8.5 ~ 9。x (Firefox, Chrome)

// const { performance } = require('perf_hooks'); // enable for node const delay = time => new Promise(res=>setTimeout(res,time)) async function doSomeLongRunningProcess(){ await delay(1000); } performance.mark('A'); (async ()=>{ await doSomeLongRunningProcess(); performance.mark('B'); performance.measure('A to B', 'A', 'B'); const measure = performance.getEntriesByName('A to B')[0]; // firefox appears to only show second precision. console.log(measure.duration); // apparently you should clean up... performance.clearMarks(); performance.clearMeasures(); // Prints the number of milliseconds between Mark 'A' and Mark 'B' })();

https://repl.it/@CodyGeisler/NodeJsPerformanceHooks

节点12.倍

https://nodejs.org/docs/latest-v12.x/api/perf_hooks.html

const { PerformanceObserver, performance } = require('perf_hooks');
const delay = time => new Promise(res => setTimeout(res, time))
async function doSomeLongRunningProcess() {
    await delay(1000);
}
const obs = new PerformanceObserver((items) => {
    console.log('PerformanceObserver A to B',items.getEntries()[0].duration);
      // apparently you should clean up...
      performance.clearMarks();
      // performance.clearMeasures(); // Not a function in Node.js 12
});
obs.observe({ entryTypes: ['measure'] });

performance.mark('A');

(async function main(){
    try{
        await performance.timerify(doSomeLongRunningProcess)();
        performance.mark('B');
        performance.measure('A to B', 'A', 'B');
    }catch(e){
        console.log('main() error',e);
    }
})();