Re: [PATCH v7 00/14] rv: Add task latency over budget RV monitor

[Gabriele Monaco <gmonaco@redhat.com>]

On Mon, 2026-10-12 at 03:39 +0800, wen.yang@linux.dev wrote:
> From: Wen Yang <wen.yang@linux.dev>
> 
> This series introduces tlob (task latency over budget), a per-task
> hybrid automaton RV monitor that measures elapsed wall-clock time across
> a user-delimited code section and emits an error when the elapsed time
> exceeds a configurable budget.

Hi Wen,

there's been a conversation at the LPC conference 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, completely converting it to BPF isn't trivial, I can keep on
reviewing it and we could upstream it in-kernel, then convert it later (together
with the work with other HA).
But I'd prioritise not affecting the in-kernel implementation much to keep it on
par with the BPF one.

I'd first like to focus on what should the rv userspace tool support for a
monitor like yours to be useful. You'd have all reporting as stdout (or any BPF
reactor you'd want to write), then we should probably support some way to set
the uprobe location and threshold before loading.
Would you really need dynamic uprobe addition?

What do you think?

Thanks,
Gabriele