Thread (4 messages) 4 messages, 3 authors, 2025-09-24

Re: [PATCH v2 1/1] tracing/sched: add 'next_policy' to trace_sched_switch

From: Steven Rostedt <rostedt@goodmis.org>
Date: 2025-09-12 14:30:01
Also in: lkml

Possibly related (same subject, not in this thread)

On Tue, 26 Aug 2025 20:48:54 +0800
Xiang Gao [off-list ref] wrote:
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:

	 72.267374: sched_switch: prev_comm=grep prev_pid=67 prev_prio=19 prev_state=S ==> next_comm=cat next_pid=66 next_prio=120 next_policy=normal
	 72.267594: sched_switch: prev_comm=cat prev_pid=66 prev_prio=120 prev_state=R+ ==> next_comm=grep next_pid=67 next_prio=19 next_policy=RR
	562.192567: sched_switch: prev_comm=grep prev_pid=85 prev_prio=19 prev_state=S ==> next_comm=cat next_pid=84 next_prio=120 next_policy=normal
	562.192944: sched_switch: prev_comm=cat prev_pid=84 prev_prio=120 prev_state=R+ ==> next_comm=grep next_pid=85 next_prio=19 next_policy=FIFO
Peter,

Are you OK with extending the sched switch tracepoint?

-- Steve
quoted hunk ↗ jump to hunk
Signed-off-by: gaoxiang17 <redacted>
---
 include/trace/events/sched.h | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 7b2645b50e78..00336211aca6 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=%s",
 		__entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
 
 		(__entry->prev_state & (TASK_REPORT_MAX - 1)) ?
@@ -263,7 +265,16 @@ 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,
+		__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"})
+	)
 );
 
 /*
  
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help