feat: added nodejs cpu profiler support

[shaleynikov]

Proof of concept of CPU nodejs profiler with tags support

Usage examples are here grafana/pyroscope@1ddf73b

TODO:

• Time value seems to have wrong cardinality
• Fix tests & add more
• Test static & dynamic tags
• Update package documentation
• Add tests for dynamic tags

[Rperry2174]

@petethepig what should this function be called to be consistent?

[petethepig]

tagWrapper

[shaleynikov]

So the current issue is:

All timing values are below 0.01s

Here is a sample profile JSON of a sample nodejs rideapp loaded withload-generator.py
https://gist.github.com/shaleynikov/1870d4529a3c9ac982e0b2c47accfce5

I can see following problems:

• wrong PeriodType of Period (or wrong Period value, compare to wall profile here https://gist.github.com/shaleynikov/a56656df9b2f9f097c3565abc37df9db)
• there is an unexpected value field with value of [0, 10000]. I'm not totally sure if it's incorrect
• I was expecting much more samples for 100hz probe during 10 seconds -- i've got near 30.

Maybe i'm missing something important about cpu profile

[shaleynikov]

https://gist.github.com/shaleynikov/1870d4529a3c9ac982e0b2c47accfce5

Okay the issue I found is Period: 10 and period type is nanoseconds which is odd to me.
So what I did is created a PR for pprof package here. Going to confirm the issue with someone else and then send an issue to the origin git

[shaleynikov]

Idle on walltime profiler was intentionally removed by DataDog

[ashtonsix]

What's the status of this PR? It looks good to me and I'd be keen to see this released

[korniltsev]

btw period bug was fixed DataDog/pprof-nodejs#61
should be included in the next 1.2.0 and we will not need fixes here

[korniltsev]

both wall and cpu right now write to our ".cpu" application, we may want to change that

[eh-am]

I am trying to run the profiler, while calculating fibonacci. This callback only gets called AFTER my fib code is ran, which is due to how js works: https://nodejs.org/en/docs/guides/dont-block-the-event-loop/#why-should-i-avoid-blocking-the-event-loop-and-the-worker-pool

[eh-am]

I mean, that's correct, the problem is that data is never flushed. Since when I call stop it simply cancels this setInterval, never getting the chance to upload the profile.

[korniltsev]

stopCpuProfile not uploads last profile, should be better now

[CLAassistant]

All committers have signed the CLA.

[ben-xD]

@shaleynikov, I guess you need to sign the CLA? as per #19 (comment)

[raphaelvigee]

What is holding this back ?

[Kidel]

please merge this, the old version is giving audit issues.

[mbombonato]

Hello guys! Any chances of this merge happening? I'm trying to implement Pyroscope for my company but I can't run this lib on NodeJS 18 and 20. I was hopping this PR could solve my issues because of the usage o @datadog/pprof.

Thanks!
/ping @petethepig 🙏

[notaphplover]

This looks great, but @datadog/pprof@4 was already released, it would be great to update it to use that version. I honestly think this might take more time to be merged than the one I currently have, so I made notaphplover/one-game#701 heavily inspired on this PR in case someone is waiting for this to be merged and has not enough time to wait.

@korniltsev I don't mind giving you a hand with the update if that helps this PR to be merged. I would prefer having an official grafana library rather than a thousand forks.

[korniltsev]

We want to have this update but It seems like I'm not going to work on it in the near future.
@notaphplover If you could open a PR that would be great, I will be happy to review and merge. We can close this one in favor of a contribution.

[notaphplover]

@korniltsev it would be my pleasure, I will submit the PR in the upcoming days

[notaphplover]

@korniltsev I will be working on #39 to provide the datadog integration. There're multiple aspects to be discussed, but I think we will be able to do it :)