Open AriPerkkio opened 2 weeks ago
I think because the child process will exit directly when you call subprocess.kill
, it has no chance to dump the profile. If you add this code process.on('SIGTERM', () => { process.exit(); })
to child process, it can dump the profile.
This seems to tie into another topic of whether subprocess.kill()
/SIGTERM
should just terminate the process with only the essential cleanups (it's debatable whether dumping cpu profiles should be considered essential), or maybe we should just invent a new method/signal/way for the subprocess to finish with also less-essential cleanups.
If you add this code
process.on('SIGTERM', () => { process.exit(); })
to child process, it can dump the profile.
Thanks for the work-around, this seems like good solution for now. I think I'll add this handler when we detect --cpu-prof
or equivalent flags in process.execArgv
.
This seems to tie into another topic of whether
subprocess.kill()
/SIGTERM
should just terminate the process with only the essential cleanups (it's debatable whether dumping cpu profiles should be considered essential)
I see, this is not a simple decision to make. And especially when comparing to node:worker_threads
I'm not sure these two were meant to be equivalent. In the documentation of .terminate()
it's stated that execution doesn't stop immediatelly like node:child_process
does:
Stop all JavaScript execution in the worker thread as soon as possible
But still I would like node:child_process
to write CPU (and other) profiles before it finishes. This will make debugging slow or stuck-like processes much easier.
Version
v20.17.0
Platform
Subsystem
No response
What steps will reproduce the bug?
How often does it reproduce? Is there a required condition?
Always
What is the expected behavior? Why is that the expected behavior?
When a child process is killed with
.kill()
, it does not generate the CPU profile that--cpu-prof
argument instructs it to do. I would expect profile to be generated.This is inconsistent with
node:worker_threads
where terminating aWorker
with.terminate()
does still generate the profile. It also makes it difficult to debug slow child processes as you cannot get profile info without waiting for graceful exit.What do you see instead?
Child process is killed and CPU profile is not written.
Additional information
No response