I think the question is straight forward.
I'm looking for something that's similar to window.performance.now() in nodejs V8 engine.
Right now I'm just using:-
var now = Date.now();
//do some processing..
console.log("time elapsed:", Date.now() - now);
But, I read that window.performance.now() is lot more accurate than using the date because of the what's defined here.
Node v8.5.0 has added Performance Timing API, which includes the performance#now(), e.g.
const {
performance
} = require('perf_hooks');
console.log('performance', performance.now());
I would only mention that three of the reasons the author gives for the preference of the timing API in the browser wouldn't seem to apply directly to a node situation, and the fourth, the inaccuracy of Javscript time, cites an article from 2008, and I would strongly caution against relying on older material regarding Javascript performance specifics, particularly given the recent round of performance improvements all the engines have made to support "HTML5" apps.
However, in answer to your question, you should look at process.hrtime()
UPDATE: The present package (available via npm install present) provides some sugar around hrtime if you'd like it.
Note: Since the version 8.5.0 of Node, you can use performance.now()
Here's a shortcut for process.hrtime() that returns milliseconds instead of microseconds:
function clock(start) {
if ( !start ) return process.hrtime();
var end = process.hrtime(start);
return Math.round((end[0]*1000) + (end[1]/1000000));
}
Usage:
var start = clock();
// do some processing that takes time
var duration = clock(start);
console.log("Took "+duration+"ms");
Will output something like "Took 200ms"
What about?
console.time('FooTimer');
// do the work
console.timeEnd('FooTimer');
process.uptime()
Official Node Documentation
"The process.uptime() method returns the number of seconds the
current Node.js process has been running.
The return value includes fractions of a second. Use Math.floor() to
get whole seconds."
Example: Measure For Loop Execution Time
const nemo = ['nemo'];
function findNemo(array) {
let start_time = process.uptime();
for (let iteration = 0; iteration < array.length; iteration++) {
if (array[iteration] === 'nemo') {
console.log("Found Nemo");
}
}
let end_time = process.uptime();
console.log("For loop took this much time: ", end_time - start_time);
}
findNemo(nemo);
Example Output
Here's a Typescript version with process.hrtime(), based on NextLocal's answer:
class Benchmark {
private start = process.hrtime();
public elapsed(): number {
const end = process.hrtime(this.start);
return Math.round((end[0] * 1000) + (end[1] / 1000000));
}
}
export = Benchmark;
Usage:
import Benchmark = require("./benchmark");
const benchmark = new Benchmark();
console.log(benchmark.elapsed());
To sum up and avoiding using perf_hooks
const performance = {
now: function(start) {
if ( !start ) return process.hrtime();
var end = process.hrtime(start);
return Math.round((end[0]*1000) + (end[1]/1000000));
}
}
console.log('performance', performance.now());
This method came into existence in version 8.5.0 of nodejs https://nodejs.org/api/perf_hooks.html#perf_hooks_performance_measurement_apis
compare solutions with and without loop.
Note down, which makes a difference performance wise ?
Try it out in JS snippets in developer tools or any JS editor.
function sum(n) {
let total = 0;
for (let i = 0; i <= n; i++) {
total += i;
}
return total;
}
var t1 = performance.now();
sum(100000000);
var t2 = performance.now();
console.log(`time elapsed: ${(t2-t1)/1000} seconds.`);
function addupto(n) {
return n * (n + 1) / 2;
}
var t3 = performance.now();
addupto(100000000);
var t4 = performance.now();
console.log(`time elapsed: ${(t4-t3)/1000} seconds.`);
Related
I would like to get the amount of time the process took to fully complete. I have this code:
console.log(`Ran ${ran} equations in ${console.timeEnd()}`)
but I don't get my expected output, which is:
Ran X equations in 33.099ms // eg
instead I get
default: 33.099ms
Ran X Equations in undefined
Note that I didn't give my console.time() a label.
How can I achieve my expected output?
console.timeEnd doesn't return anything; it's part of the console, as you know. Because console.timeEnd counts in milliseconds with decimal places (unlike Date.now()), the closest thing you'll get is with performance.now(). We can create a custom time function:
class Time {
constructor() {
this.time = performance.now();
}
end() {
return (performance.now() - this.time).toFixed(3); // round number to lower decimal precision, like console.time()
}
}
const time = new Time();
console.time("Console measurement");
let dummyVar = 0;
for(let i = 0; i < 1000000; i++) {
// do some time consuming task
dummyVar += i;
}
console.log("Custom measurement:", time.end() + "ms");
console.timeEnd("Console measurement");
I intentionally returned a number and not a string (with "ms" at the end) so you could use it better. Obviously, if you want to represent the exact output of console.timeEnd(), simply append + "ms" to the expression in Time#end:
class Time {
constructor() {
this.time = performance.now();
}
end() {
return (performance.now() - this.time).toFixed(3) + "ms";
}
}
const time = new Time();
// dummy example
setTimeout(() => console.log(`Ran X equations in ${time.end()}`), Math.floor(Math.random() * 100));
console.timeEnd() returns undefined, not what it logs. To get very close to the desired output, label the timer with the descriptive string...
const ran = 4; // you'll need to know ran before starting the timer
const label = `Ran ${ran} equations in`;
console.time(label);
// do some time consuming stuff
alert('wait a sec, then press ok')
console.timeEnd(label);
The process.cpuUsage() function displays some weird microsecond values.
How to get cpu usage in percentage?
You can achieve this using the additional os native module to get informations about your CPUs:
const os = require('os');
// Take the first CPU, considering every CPUs have the same specs
// and every NodeJS process only uses one at a time.
const cpus = os.cpus();
const cpu = cpus[0];
// Accumulate every CPU times values
const total = Object.values(cpu.times).reduce(
(acc, tv) => acc + tv, 0
);
// Normalize the one returned by process.cpuUsage()
// (microseconds VS miliseconds)
const usage = process.cpuUsage();
const currentCPUUsage = (usage.user + usage.system) * 1000;
// Find out the percentage used for this specific CPU
const perc = currentCPUUsage / total * 100;
console.log(`CPU Usage (%): ${perc}`);
If you want to get the global CPU usage (taking all your CPUs into account), you need to accumulate every times of every CPUs, not only the first one, but that should be less useful in most cases.
Note that only the "system" time can use more than the first CPU because the calls can run in other threads separated from the NodeJS core.
Sources :
https://nodejs.org/api/os.html#os_os_cpus
https://nodejs.org/api/process.html#process_process_cpuusage_previousvalue
An alternative, assuming you are running node under linux/macos O.S. is:
var exec = require("child_process").exec;
function getProcessPercent() {
// GET current node process id.
const pid = process.pid;
console.log(pid);
//linux command to get cpu percentage for the specific Process Id.
var cmd = `ps up "${pid}" | tail -n1 | tr -s ' ' | cut -f3 -d' '`;
setInterval(() => {
//executes the command and returns the percentage value
exec(cmd, function (err, percentValue) {
if (err) {
console.log("Command `ps` returned an error!");
} else {
console.log(`${percentValue* 1}%`);
}
});
}, 1000);
}
getProcessPercent();
If your O.S is windows, your command must be different. As i'm not running windows i can't tell to you the exact command, but you can start from here:
tasklist
get-process
WMIC
You can also check the platform with process.platform and do an if/else statment setting the right command for the specific OS.
Before answering we need to take care about a couple of facts:
Node.js does not uses only one CPU, but every async I/O operation may use additional CPUs
the times returned by process.cpuUsage are cumulative of all CPUs used by the Node.js process
so to calculate the CPU usage of Node.js considering all the CPUs of the host, we could use something similar to:
const ncpu = require("os").cpus().length;
let previousTime = new Date().getTime();
let previousUsage = process.cpuUsage();
let lastUsage;
setInterval(() => {
const currentUsage = process.cpuUsage(previousUsage);
previousUsage = process.cpuUsage();
// we can't do simply times / 10000 / ncpu because we can't trust
// setInterval is executed exactly every 1.000.000 microseconds
const currentTime = new Date().getTime();
// times from process.cpuUsage are in microseconds while delta time in milliseconds
// * 10 to have the value in percentage for only one cpu
// * ncpu to have the percentage for all cpus af the host
// this should match top's %CPU
const timeDelta = (currentTime - previousTime) * 10;
// this would take care of CPUs number of the host
// const timeDelta = (currentTime - previousTime) * 10 * ncpu;
const { user, system } = currentUsage;
lastUsage = { system: system / timeDelta, total: (system + user) / timeDelta, user: user / timeDelta };
previousTime = currentTime;
console.log(lastUsage);
}, 1000);
or we can read the value of lastUsage from where we need it rather printing it to the console.
Try using the below code to get cpu usage in %
var startTime = process.hrtime()
var startUsage = process.cpuUsage()
// spin the CPU for 500 milliseconds
var now = Date.now()
while (Date.now() - now < 500)
var elapTime = process.hrtime(startTime)
var elapUsage = process.cpuUsage(startUsage)
var elapTimeMS = secNSec2ms(elapTime)
var elapUserMS = secNSec2ms(elapUsage.user)
var elapSystMS = secNSec2ms(elapUsage.system)
var cpuPercent = Math.round(100 * (elapUserMS + elapSystMS) / elapTimeMS)
console.log('elapsed time ms: ', elapTimeMS)
console.log('elapsed user ms: ', elapUserMS)
console.log('elapsed system ms:', elapSystMS)
console.log('cpu percent: ', cpuPercent)
function secNSec2ms (secNSec) {
return secNSec[0] * 1000 + secNSec[1] / 1000000
}
try tweaking the secNSec2ms function to the following to check if it solves your problem.
function secNSec2ms(secNSec) {
if (Array.isArray(secNSec))
return secNSec[0] * 1000 + secNSec[1] / 1000000 return secNSec / 1000;
}
I'm using NodeJs.
I received constantly request from server.
I'm added some variable like createdTime to it and saved to the database.
when I sorted data by createdTime in some case It is not reliable, It is Repeated
How can I make differentiate between them ?
I do not want to count request.
I do not like to change timestamp's format.
var createdTime = new Date().getTime();
Here's a method of combining a counter with the current time to allow you to have as many as 1000 separate transactions within the same ms that are all uniquely numbered, but still a time-based value.
And, here's a working snippet to illustrate:
// this guarantees a unique time-based id
// as long as you don't have more than 1000
// requests in the same ms
var getTransactionID = (function() {
var lastTime, counter = 0;
return function() {
var now = Date.now();
if (now !== lastTime) {
lastTime = now;
counter = 0;
} else {
++counter;
}
return (now * 1000) + counter;
}
})();
for (var i = 0; i < 100; i++) {
document.write(getTransactionID() + "<br>");
}
If you want something that is likely to work across clusters, you can use process.hrtime() to use the high resolution timer instead of the counter and then make the id be a string that could be parsed into a relative time if needed. Since this requires node.js, I can't make a working snippet here in the browser, but here's the idea:
// this makes a unique time-based id
function getTransactionID () {
var now = Date.now();
var hrtime = process.hrtime();
return now + "." + ((hrtime[0] * 1e9) + hrtime[1]);
}
Due to my low rep I can't add a comment but it looks like you are needing to go beyond milliseconds.Maybe this stackoverflow question can help you
How to get a microtime in Node.js?
I want to calculate the average running time of a function in JavaScript like this:
time = 0;
while(1000) {
time1 = performance.now();
function();
time2 = performance.now();
time += (time2-time1);
}
The problem is that only the first loop the time interval is about 60ms and the following loop the interval is nearly zero.
So I changed the code to:
time1 = performance.now();
while(1000000) {
function();
}
time2 = performance.now();
time = (time2-time1);
The running time is about 4 seconds.
I guess maybe it is because of the automatic optimisation.
If it is this case, are there any approaches to close the optimisation?
You've most likely caused the browser to hand off that code to its JIT compiler. The first run is always through the interpreter (slow). Hot code gets put through the JIT and the resulting native (fast) code is then used.
This is automatic and generally out of your hands to control. You can disable the Firefox JIT compiler by using 'with' in a script.
with({}) {}
Add this to the top of your script and the JIT will be disabled for your script.
You can also use console.time and console.endTime function to calculate the running time.
example:
console.time('profile 1');
for ( var i=0; i < 100000; i++) {
var arr = new Array();
}
console.timeEnd('profile 1');//profile 1: 108.492ms
console.time('profile 2');
for ( var i=0; i < 100000; i++) {
var arr = [];
}
console.timeEnd('profile 2');//profile 2: 81.907ms
I'm looking into the speed of JavaScript parsers in web browsers, importantly it needs to be easy to demonstrate. I came up with a simple test - the idea being that each script block is parsed and executed individually, so a large block of script could be timed:
<script>var start = new Date().getTime();</script>
<script>
/*! jQuery v1.8.2 jquery.com | jquery.org/license */
...
</script>
<script>alert ( new Date().getTime() - start );</script>
Superficially this appears to work, removing the middle script block will result in a negligible time.
However I'm not certain that my logic is not fundamentally flawed.
It seems the answer is broadly yes, but to get a reasonable result (like anything else) the test should be run many times to level out the effects of compilation caching and garbage collection. The test above can easily be placed into the Parse-n-Load library: http://carlos.bueno.org/2010/02/measuring-javascript-parse-and-load.html
Thanks for your help
This may be of help!
var start = new Date().getTime();
var end = new Date().getTime();
var time = end - start;
alert('Execution time: ' + time);
If you want to benchmark your JavaScript, include MilliSeconds etc.
var t = new Date();
var start = t.getTime()*1000 + t.getMilliseconds();
/* do something*/
var t2 = new Date();
var end = t2.getTime()*1000 + t.getMilliseconds();
alert("The Code needed " + (end-start) + " milliseconds. That are " + parseInt((end-start)/1000) + " seconds.");
You might want to differentiate between parsing and execution time. You could do something like
<script>start = Date.now();</script>
<script>
parsed = Date.now();
/*! jQuery v1.8.2 jquery.com | jquery.org/license */
…
</script>
<script>var end = Date.now();
alert ( "parsed in " + (parsed - start) + "ms" );
alert ( "executed in " + (end - parsed) + "ms" );
alert ( "overall time: " + (end - start) + "ms" );
</script>
With that you might be able to detect cached parse trees etc. Yet, for more distinct information have a look at your developer tools, they show such type of information in their profiler section. Or in Opera, it's included in the load process of scripts in the network panel.
This answer is from 10 years in the future.
There are a number of approaches to timing web page processes including:
Date-related methods:
Date.now();
and:
console.time-related methods:
console.time('myTimer');
console.timeLog('myTimer');
console.timeEnd('myTimer');
but, since late 2015, the ideal way to time web page processes using high-resolution timestamps has been:
window.performance.now();
Using Performance:
The Performance interface, accessed via window.performance has numerous methods, including:
timeOrigin
mark
measure
getEntries
toJSON
and more.
But in order to time a script, all you need is window.performance.now():
let scriptStart = window.performance.now();
let scriptEnd = window.performance.now();
let scriptDuration = (scriptEnd - scriptStart);
Working Example:
let paragraph = document.querySelector('p');
let button = document.querySelector('button');
const runTimedScript = () => {
let scriptStart = window.performance.now();
for (let i = 0; i < 10000; i++) {
paragraph.textContent = 'Loop iteration ' + (i + 1);
}
let scriptEnd = window.performance.now();
let scriptDuration = (scriptEnd - scriptStart);
button.textContent = 'Re-run Script';
console.log('The script ran in ' + scriptDuration + ' milliseconds');
}
button.addEventListener('click', runTimedScript, false);
button {
cursor: pointer;
}
<p></p>
<button type="button">Run Script</button>
<p>To see how long the script takes to run,<br />
click the button above repeatedly.</p>
Further Reading:
To find out more about the Performance Interface, see:
Performance API (MDN)