[ Adding scheduler maintainers ]
On Fri, 22 Aug 2025 10:02:09 -0400
Steven Rostedt <rost...@goodmis.org> wrote:
> On Fri, 22 Aug 2025 18:51:13 +0800
> Xiang Gao <gxxa03070...@gmail.com> wrote:
>
> > From: gaoxiang17 <gaoxian...@xiaomi.com>
> >
> > Sometimes, when analyzing some real-time process issues, it is necessary to
> > know the sched policy.
> >
> > Show up in the trace as:
> >
> > 113.457176: sched_switch: prev_comm=kcompactd0 prev_pid=30
> > prev_prio=120 prev_state=S ==> next_comm=kworker/u4:1 next_pid=27
> > next_prio=120 next_policy=0
> > 113.457282: sched_switch: prev_comm=kworker/u4:1 prev_pid=27
> > prev_prio=120 prev_state=I ==> next_comm=swapper/0 next_pid=0 next_prio=120
> > next_policy=0
> > 113.461166: sched_switch: prev_comm=swapper/0 prev_pid=0
> > prev_prio=120 prev_state=R ==> next_comm=kworker/u4:1 next_pid=27
> > next_prio=120 next_policy=0
> >
> > Signed-off-by: gaoxiang17 <gaoxian...@xiaomi.com>
> > ---
> > include/trace/events/sched.h | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
> > index 7b2645b50e78..b416b7bafee4 100644
> > --- a/include/trace/events/sched.h
> > +++ b/include/trace/events/sched.h
> > @@ -234,6 +234,7 @@ TRACE_EVENT(sched_switch,
> > __array( char, next_comm, TASK_COMM_LEN )
> > __field( pid_t, next_pid )
> > __field( int, next_prio )
> > + __field( unsigned int, next_policy )
> > ),
> >
> > TP_fast_assign(
> > @@ -244,10 +245,11 @@ TRACE_EVENT(sched_switch,
> > memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
> > __entry->next_pid = next->pid;
> > __entry->next_prio = next->prio;
> > + __entry->next_policy = next->policy;
> > /* XXX SCHED_DEADLINE */
> > ),
> >
> > - TP_printk("prev_comm=%s prev_pid=%d prev_prio=%d prev_state=%s%s ==>
> > next_comm=%s next_pid=%d next_prio=%d",
> > + TP_printk("prev_comm=%s prev_pid=%d prev_prio=%d prev_state=%s%s ==>
> > next_comm=%s next_pid=%d next_prio=%d next_policy=%u",
> > __entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
> >
> > (__entry->prev_state & (TASK_REPORT_MAX - 1)) ?
> > @@ -263,7 +265,7 @@ TRACE_EVENT(sched_switch,
> > "R",
> >
> > __entry->prev_state & TASK_REPORT_MAX ? "+" : "",
> > - __entry->next_comm, __entry->next_pid, __entry->next_prio)
> > + __entry->next_comm, __entry->next_pid, __entry->next_prio,
> > __entry->next_policy)
>
>
> I'm fine with this change, but I'm not sure how Peter feels about updating
> scheduler tracepoints. That said, why not show the policy name?
Oh, and trace events are owned by the subsystem maintainers not the tracing
maintainers. You need to Cc them.
-- Steve
>
> TP_printk("prev_comm=%s prev_pid=%d prev_prio=%d prev_state=%s%s ==>
> next_comm=%s next_pid=%d next_prio=%d next_policy=%s",
> [..]
> __entry->next_comm, __entry->next_pid, __entry->next_prio,
> __print_symbolic(__entry->next_policy,
> { SCHED_NORMAL, "normal" },
> { SCHED_FIFO, "FIFO" },
> { SCHED_RR, "RR" },
> { SCHED_BATCH, "batch" },
> { SCHED_IDLE, "idle" },
> { SCHED_DEADLINE, "deadline" },
> { SCHED_EXT, "sched_ext"}))
>
> -- Steve
>
>
>
>
>
>
> > );
> >
> > /*
>
