Re: [PATCH v2 0/3] rv: per-edge dwell-time statistics for per-cpu monitors

[Gabriele Monaco <gmonaco@redhat.com>]

On Fri, 2026-09-11 at 14:34 +0200, Tobias Schaffner wrote:
> Hi Steven, Gabriele,
> 
> I am using the RV system for a downstream project called EVL (aka Xenomai4).
> It is a small co-kernel system, small enough that I can model the whole
> co-kernel with RV instead of just a fragment of it.
> 
> The patches in this series add a per-monitor "stats" file that exposes how
> often an edge has been visited and the dwell time in the prior state for
> per-cpu monitors.
> 
> This allows me to not only check if the model is correct but also to see if
> all paths are exercised by my stress tooling and to decompose the latency of
> the co-kernel's wakeup path.
> 
> I think that some of the upstream monitors like e.g. the sts monitor could
> also profit from this.

Hi Tobias,

there's been a conversation at LPC about completely migrating RV to BPF.
While we aren't sure of its feasibility yet, and it will take time, it's
something to keep in mind for new contributions.

First of all, would dropping RV in-kernel support negatively affect your current
workflow?

About this series, I believe we could implement the same using BPF maps without
too much effort, then the rv userspace tool could display them nicely.

What do you think?

Thanks,
Gabriele