Improve the V8 Profiler performance #444
Comments
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Removing from the agenda until we come up with benchmarks for the performance issue. |
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This issue is stale because it has been open many days with no activity. It will be closed soon unless the stale label is removed or a comment is made. |
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I've tried to reproduce this behavior but it looks like was fixed on v14 and above. Code: const inspector = require('inspector');
const fs = require('fs');
const session = new inspector.Session();
session.connect();
console.time('enable')
session.post('Profiler.enable', () => {
console.timeEnd('enable')
let a = [];
for (let i = 0; i < 1000000; i++) {
const f = new Function("a", "b", "return a + b");
f(i, i - 1);
a.push(f);
}
console.time('start')
session.post('Profiler.start', () => {
console.timeEnd('start')
console.time('stop')
session.post('Profiler.stop', (err, { profile }) => {
console.timeEnd('stop')
if (!err) {
fs.writeFileSync('./profile.cpuprofile', JSON.stringify(profile));
}
});
});
});v10 $ node bench-profiler.js
enable: 0.293ms
start: 610.000ms
stop: 235.631msv12 $ node bench-profiler.js
enable: 0.404ms
start: 640.016ms
stop: 0.473msv14 $ node bench-profiler.js
enable: 0.682ms
start: 58.032ms
stop: 0.472msv16 $ node bench-profiler.js
enable: 1.621ms
start: 53.174ms
stop: 0.695ms@Flarna I'm tagging you because I've seen your code example from: #148 (comment) |
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We discussed and sounds reasonable to close this issue since the results look good for the production environment. |
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Hi, @RafaelGSS, can we reopen this issue? I ran the above bench program in
yet on I went backwards on 16 LTS, and it's fast - sometimes - on and it appears always fast, but not as fast as 14 or 17, on These were all run on a macbook pro 2020, intel. |
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Hey! Are you able to send a reproducible code? |
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Yes, I ran the exact script referenced above that you posted from the original thread. I did not attempt to repro this on other machines / OS, only on mac (Big Sur). I didn't try on linux, for example. |
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Oh, ok. I'll check soon |
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This issue is stale because it has been open many days with no activity. It will be closed soon unless the stale label is removed or a comment is made. |
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Recently, I had no time to validate it. Does anyone in @nodejs/diagnostics interested in this discovery? |
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If I got it right, we should understand why the profiler takes too much to stop on Node 16.x and 17.x? |
Checking how much time is it taking in all Node.js versions would be a great start. |
Neat! I could give it a try ^^. Feel free to share any resource that could help me. I remember you posted that: /~https://github.com/RafaelGSS/nodejs-bench-operations Could I use a similar approach? |
I think the snippet I sent above would work as well. #444 (comment) |
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Hey 👋 Make a simple script and put the results here: /~https://github.com/tony-go/v8-profiler-performance What I did:
I keep the same output but let me know if you prefer a table with average etc... Sorry if it looks a bit bikeshed, but it's my first time ^^ |
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Thank you @tony-go. I've run it locally and the max spike I got was 1.5sec ======= iteration number 1 for node v14.19.3 ========
enable: 0.246ms
start: 57.586ms
stop: 0.447ms
======= iteration number 2 for node v14.19.3 ========
enable: 0.25ms
start: 56.623ms
stop: 0.435ms
======= iteration number 3 for node v14.19.3 ========
enable: 0.238ms
start: 58.386ms
stop: 0.445ms
======= iteration number 4 for node v14.19.3 ========
enable: 0.246ms
start: 57.457ms
stop: 0.456ms
======= iteration number 5 for node v14.19.3 ========
enable: 0.267ms
start: 59.748ms
stop: 0.597ms
======= iteration number 6 for node v14.19.3 ========
enable: 0.249ms
start: 56.702ms
stop: 0.444ms
======= iteration number 7 for node v14.19.3 ========
enable: 0.236ms
start: 58.028ms
stop: 0.477ms
======= iteration number 8 for node v14.19.3 ========
enable: 0.245ms
start: 57.485ms
stop: 0.434ms
======= iteration number 9 for node v14.19.3 ========
enable: 0.245ms
start: 57.501ms
stop: 0.455ms
======= iteration number 10 for node v14.19.3 ========
enable: 0.247ms
start: 59.6ms
stop: 0.437msThere are several variables that might affect this benchmark such as page faults and so on. Nevertheless, I think the results in the latest version are acceptable |
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@lastquestion I'll close it. In case you think this need to be fixed, please provide a bit more information of your use case. Thank you! |
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Good :)
For my personal culture: if you could share more information regarding stuff I should avoid when I write a benchmark it should be great :) |
As previously mentioned on #148 a lot of work was done on CPU Profiler.
The only tool for profiling NodeJS cross-platform is the usage of
Profiler.startandProfiler.stop. However, this dynamic instrumentation blocks the event-loop because it needs to iterate over all functions to map. (CpuProfiler::StartProfiling more specifically) and it is harmful to production environments.This issue is to discuss some ways to improve these usages in the production environment.
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