cobalt/tracing: Trace changes of the current thread priority

Specifically useful to validate scheduling during PI or PP phases.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

kernel/cobalt/sched.c

@@ -466,6 +466,8 @@ bool xnsched_set_effective_priority(struct xnthread *thread, int prio)
 
 	thread->cprio = prio;
 
+	trace_cobalt_thread_set_current_prio(thread);
+
 	return true;
 }
 
@@ -507,6 +509,8 @@ void xnsched_track_policy(struct xnthread *thread,
 			xnsched_enqueue(thread);
 	}
 
+	trace_cobalt_thread_set_current_prio(thread);
+
 	xnsched_set_resched(thread->sched);
 }
 
@@ -533,6 +537,8 @@ void xnsched_protect_priority(struct xnthread *thread, int prio)
 	if (xnthread_test_state(thread, XNREADY))
 		xnsched_enqueue(thread);
 
+	trace_cobalt_thread_set_current_prio(thread);
+
 	xnsched_set_resched(thread->sched);
 }
 

kernel/cobalt/trace/cobalt-core.h

@@ -309,6 +309,26 @@ TRACE_EVENT(cobalt_thread_fault,
 		  __entry->type)
 );
 
+TRACE_EVENT(cobalt_thread_set_current_prio,
+	TP_PROTO(struct xnthread *thread),
+	TP_ARGS(thread),
+
+	TP_STRUCT__entry(
+		__field(struct xnthread *, thread)
+		__string(name, thread->name)
+		__field(int, cprio)
+	),
+
+	TP_fast_assign(
+		__entry->thread	= thread;
+		__assign_str(name, thread->name);
+		__entry->cprio = xnthread_current_priority(thread);
+	),
+
+	TP_printk("thread=%p(%s) prio=%d",
+		  __entry->thread, __get_str(name), __entry->cprio)
+);
+
 DEFINE_EVENT(thread_event, cobalt_thread_start,
 	TP_PROTO(struct xnthread *thread),
 	TP_ARGS(thread)