Re: [PATCH] tracing/sched: add 'next_policy' to trace_sched_switch
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2025-08-22 14:02:07
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On Fri, 22 Aug 2025 18:51:13 +0800 Xiang Gao [off-list ref] wrote:
quoted hunk ↗ jump to hunk
From: gaoxiang17 <redacted> 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 <redacted> --- 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
); /*