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
老问题，但一个简单的API和轻量级的解决方案;您可以使用perfy，它在内部使用高分辨率实时(process.hrtime)。
var perfy = require('perfy');
function end(label) {
return function (err, saved) {
console.log(err ? 'Error' : 'Saved');
console.log( perfy.end(label).time ); // <——— result: seconds.milliseconds
};
}
for (var i = 1; i < LIMIT; i++) {
var label = 'db-save-' + i;
perfy.start(label); // <——— start and mark time
db.users.save({ id: i, name: 'MongoUser [' + i + ']' }, end(label));
}
注意，每次调用perfy.end(label)时，该实例都会被自动销毁。
披露:受D.Deriso的回答启发，编写了这个模块。文档。
其他回答
使用Node.js console.time()和console.timeEnd():
var i;
console.time("dbsave");
for(i = 1; i < LIMIT; i++){
db.users.save({id : i, name : "MongoUser [" + i + "]"}, end);
}
end = function(err, saved) {
console.log(( err || !saved )?"Error":"Saved");
if(--i === 1){
console.timeEnd("dbsave");
}
};
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。
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
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);
}
})();
我需要它是累积的，用来测量不同的东西。 构建这些函数:
function startMeasuring(key) {
measureTimers[key] = process.hrtime();
}
function stopMeasuring(key) {
if (!measures[key]) {
measures[key] = 0;
}
let hrtime = process.hrtime(measureTimers[key]);
measures[key] += hrtime[0] + hrtime[1] / 1e9;
measureTimers[key] = null;
}
用法:
startMeasuring("first Promise");
startMeasuring("first and second Promises");
await new Promise((resolve) => {
setTimeout(resolve, 1400);
});
stopMeasuring("first Promise");
stopMeasuring("first and second Promises");
startMeasuring("first and second Promises");
await new Promise((resolve) => {
setTimeout(resolve, 600);
});
stopMeasuring("first and second Promises");
console.log("Measure Results", measures);
/*
Measusre Results {
setting: 0.00002375,
'first Promise': 1.409392916,
'first and second Promise': 2.015160376
}
*/
