Re: [PATCH v2 01/15] sched: Add task enqueue/dequeue trace points

[Gabriele Monaco]

On Thu, 2026-10-01 at 17:49 +0200, Peter Zijlstra wrote:
> On Thu, Oct 01, 2026 at 05:20:28PM +0200, Gabriele Monaco wrote:
> > From: Nam Cao <namcao@xxxxxxxxxxxxx>
> > 
> > Add trace points into enqueue_task() and dequeue_task().
> > 
> > Signed-off-by: Nam Cao <namcao@xxxxxxxxxxxxx>
> > Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> 
> Obviously I don't remember anything at all. But also, you 'forgot' to
> send me the rest of the patches which might hold a clue. As is I'm
> clueless as to why we want this, since the Changelog also offers none.

Right..

This commit is part of [1], but borrowed from [2], which is actually more
interesting to understand why I need those tracepoints.

[2] contains 3 other RV deadline monitors, I should have at least CC'd you in
[3] and [4].. Essentially the enqueue and dequeue tracepoints are used to:

 * model the event from dl_server idle to ready (a new fair task is available)
 * understand when a task is moved to and from another scheduler runqueue

Thanks,
Gabriele

[1] - https://lore.kernel.org/lkml/20261001152042.124445-1-gmonaco@xxxxxxxxxx
[2] - https://lore.kernel.org/lkml/20260929124908.177676-1-gmonaco@xxxxxxxxxx
[3] - https://lore.kernel.org/lkml/20260929124908.177676-8-gmonaco@xxxxxxxxxx
[4] - https://lore.kernel.org/lkml/20260929124908.177676-9-gmonaco@xxxxxxxxxx