flamegraph extend flamegraph to take an optional pid and timespan

Adding a timeout to flamegraph would be nice for long running commands.

Example of a command printing output once per second forever: # flamegraph -o example.svg vfsstat 1

In this scenario being able to pass a 30s timeout value that results in tick-30s { exit(0) }' would be great. # flamegraph -t 30s -o example.svg vfsstat 1

Additionally being able to run flamegraph against an already running process by specifying a pid and timeout would be nice. flamegraph -p $(pgrep my-server) -t 30s -o server.svg

Mar 13 '19 21:03 papertigers

Another useful argument would be to defer collection until a certain amount of time has passed, to avoid having a big flamegraph of your application starting up followed by a short section you're actually interested in.

Mar 13 '19 22:03 estebank

I'm quite in-favor of adding this flag. Also, once it is in place, this library can easily allow applications to generate flamegraphs targeting themselves through the library API.

Mar 14 '19 14:03 spacejam

having it as a -p option is a bad idea, since the package selection in the workspace of the original cargo command is done with this flag. having it available via --pid is fine

Mar 05 '20 22:03 Stunkymonkey

FWIW I use the pid argument of py-spy all the time: https://github.com/benfred/py-spy

Massively helpful for profiling long-running service applications

Sep 22 '20 13:09 willstott101

+1 to add --pid please, I would love to be able to profile something that is already running for an interval

Jul 12 '22 05:07 ckcr4lyf

The flamegraph binary already exposes --pid. I suppose this issue is only still open because we don't support a time span (or delay) yet.

Jul 25 '22 08:07 djc

The flamegraph binary already exposes --pid. I suppose this issue is only still open because we don't support a time span (or delay) yet.

I never tried it, but if so, would be nice to add to the documentation as well (https://github.com/flamegraph-rs/flamegraph#usage) . I will test the pid feature tonight

Jul 25 '22 10:07 ckcr4lyf

Would be great if you can submit a PR to clarify the existence of this option in the README.

Jul 25 '22 11:07 djc

Tested, it works. Will make a PR!

Jul 25 '22 15:07 ckcr4lyf

Looks like this was accidentally closed? A way to stop recording before the process ends would be nice to have.

Sep 07 '24 11:09 fenhl

I won't be able to work on that myself, but would be happy to review a PR.

Sep 07 '24 11:09 djc