Hi!
On 14/08/25 17:08, Gabriele Monaco wrote:
> Add the following tracepoints:
>
> * sched_dl_throttle(dl):
> Called when a deadline entity is throttled
> * sched_dl_replenish(dl):
> Called when a deadline entity's runtime is replenished
> * sched_dl_server_start(dl):
> Called when a deadline server is started
> * sched_dl_server_stop(dl, hard):
> Called when a deadline server is stopped (hard) or put to idle
> waiting for the next period (!hard)
>
> Those tracepoints can be useful to validate the deadline scheduler with
> RV and are not exported to tracefs.
>
> Signed-off-by: Gabriele Monaco <[email protected]>
> ---
> include/trace/events/sched.h | 55 ++++++++++++++++++++++++++++++++++++
> kernel/sched/deadline.c | 8 ++++++
> 2 files changed, 63 insertions(+)
>
> diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
> index 7b2645b50e78..f34cc1dc4a13 100644
> --- a/include/trace/events/sched.h
> +++ b/include/trace/events/sched.h
> @@ -609,6 +609,45 @@ TRACE_EVENT(sched_pi_setprio,
> __entry->oldprio, __entry->newprio)
> );
>
> +/*
> +DECLARE_EVENT_CLASS(sched_dl_template,
> +
> + TP_PROTO(struct sched_dl_entity *dl),
> +
> + TP_ARGS(dl),
> +
> + TP_STRUCT__entry(
> + __field( struct task_struct *, tsk )
> + __string( comm, dl->dl_server ? "server" :
> container_of(dl, struct task_struct, dl)->comm )
> + __field( pid_t, pid )
> + __field( s64, runtime )
> + __field( u64, deadline )
> + __field( int, dl_yielded )
I wonder if, while we are at it, we want to print all the other fields
as well (they might turn out to be useful). That would be
.:: static (easier to retrieve with just a trace)
- dl_runtime
- dl_deadline
- dl_period
.:: behaviour (RECLAIM)
- flags
.:: state
- dl_ bool flags in addition to dl_yielded
> + ),
> +
> + TP_fast_assign(
> + __assign_str(comm);
> + __entry->pid = dl->dl_server ? -1 : container_of(dl,
> struct task_struct, dl)->pid;
> + __entry->runtime = dl->runtime;
> + __entry->deadline = dl->deadline;
> + __entry->dl_yielded = dl->dl_yielded;
> + ),
> +
> + TP_printk("comm=%s pid=%d runtime=%lld deadline=%lld yielded=%d",
^^^
llu ?
> + __get_str(comm), __entry->pid,
> + __entry->runtime, __entry->deadline,
> + __entry->dl_yielded)
> +);
...
> @@ -1482,6 +1486,7 @@ static void update_curr_dl_se(struct rq *rq, struct
> sched_dl_entity *dl_se, s64
>
> throttle:
> if (dl_runtime_exceeded(dl_se) || dl_se->dl_yielded) {
> + trace_sched_dl_throttle_tp(dl_se);
> dl_se->dl_throttled = 1;
I believe we also need to trace the dl_check_constrained_dl() throttle,
please take a look.
Also - we discussed this point a little already offline - but I still
wonder if we have to do anything special for dl-server defer. Those
entities are started as throttled until 0-lag, so maybe we should still
trace them explicitly as so?
In addition, since it's related, maybe we should do something about
sched_switch event, that is currently not aware of deadlines, runtimes,
etc.
Thanks,
Juri
