Bpftune crashes when suspending

[Tungsten842]

1. Press the power button to suspend the laptop.
2. The bpftune service stops.

❯ journalctl -u bpftune.service
Aug 19 10:10:50 nixos-dell systemd[1]: Started BPF-based auto-tuning of system parameters.
Aug 19 10:10:50 nixos-dell bpftune[7957]: bpftune works fully
Aug 19 10:10:50 nixos-dell bpftune[7957]: bpftune supports per-netns policy (via netns cookie)
Aug 19 10:11:41 nixos-dell bpftune[7957]: ring_buffer__poll: Interrupted system call
Aug 19 10:11:43 nixos-dell systemd[1]: bpftune.service: Deactivated successfully.
Aug 19 10:11:43 nixos-dell systemd[1]: bpftune.service: Consumed 4.180s CPU time, no IO, no IP traffic.

OS: nixos-unstable

[alan-maguire]

a few questions

• does the service start again on resume? is it unusual for services to stop in suspend?
• the above log is expected and doesn't indicate crash (just that the polling was interrupted by service stopping). we see the same on normal exit. were there other signs of crash like coredump?

[alan-maguire]

i've removed the error reporting for the case where a signal is received now: #55

[Tungsten842]

a few questions

* does the service start again on resume? is it unusual for services to stop in suspend?

* the above log is expected and doesn't indicate crash (just that the polling was interrupted by service stopping). we see the same on normal exit. were there other signs of crash like coredump?

The service doesn't start again on resume, it says: Active: inactive (dead) since Mon 2023-08-21 17:14:49 CEST; 28s ago
I think that it is pretty unusual for a service to stop in suspend.
Coredumpctl is empty so it's seems that the service didn't crash.

Also I was able to observe the same issue without the service.
Just starting bpftune in a terminal and then suspending the laptop causes the same thing:

❯ sudo bpftune -s
bpftune: bpftune works fully
bpftune: bpftune supports per-netns policy (via netns cookie)
bpftune: ring_buffer__poll: Interrupted system call

[alan-maguire]

#56 fixes the issue for me (tested via "systemctl suspend"). I've merged it into main; can you try rebuilding/retesting? thanks!

[Tungsten842]

#56 fixes the issue for me (tested via "systemctl suspend"). I've merged it into main; can you try rebuilding/retesting? thanks!

It works now🎉

[alan-maguire]

wow, thanks for testing so quickly!