Re: [PATCH v3 0/7] rtla/timerlat: Add --bpf-action option

From: Crystal Wood

Date: Fri Oct 31 2025 - 09:49:13 EST


On Mon, 2025-10-27 at 16:33 +0100, Tomas Glozar wrote:
> This patchset extends rtla-timerlat's BPF support with the option of
> executing a user-supplied BPF program on latency threshold overflow.
>
> See the supplied example and documentation for how to create a program.
> bpf_tail_call() is used to chain the program with the built-in BPF
> sample collection program, if the threshold is hit.
>
> The feature can be used for both in-kernel data collection and sending
> signals to userspace directly from the kernel, if the kernel version
> allows it.
>
> Note: The patchset will have to be rebased on top of [1], or vice versa,
> since they both touch stop_tracing() ([1] adds one call of it, and this
> patchset adds an extra argument to it).

Probably best to add an updated version of that patch to this patchset.


> v3 changes:
> - Add tests/bpf/bpf_action_map.c to test commit (forgot to run
> git add before).

Might be nice to build that as part of "all", for the sake of people
running the tests directly (FWIW, I still don't see anything in the
makefile or engine.sh documenting how to satisfy that dependency).

In any case:
Reviewed-by: Crystal Wood <crwood@xxxxxxxxxx>


-Crystal