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?
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
> );
>
> /*
