Add SCHED, SCHED2, TICK, and CXS overhead tracepoints

This patch integrates the overhead tracepoints into the Linux
scheduler that are compatible with plain vanilla Linux (i.e., not
specific to LITMUS^RT plugins).  This can be used to measure the
overheads of an otherwise unmodified kernel.

1 files changed, 19 insertions, 1 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index a4c8c093f6bc..5a51ce671fd2 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -86,6 +86,8 @@
 #include "../workqueue_internal.h"
 #include "../smpboot.h"
 
+#include <litmus/trace.h>
+
 #define CREATE_TRACE_POINTS
 #include <trace/events/sched.h>
 
@@ -2742,6 +2744,8 @@ void scheduler_tick(void)
 
         sched_clock_tick();
 
+        TS_TICK_START(current);
+
         raw_spin_lock(&rq->lock);
         update_rq_clock(rq);
         update_cpu_load_active(rq);
@@ -2755,6 +2759,8 @@ void scheduler_tick(void)
         trigger_load_balance(rq, cpu);
 #endif
         rq_last_tick_reset(rq);
+
+        TS_TICK_END(current);
 }
 
 #ifdef CONFIG_NO_HZ_FULL
@@ -2966,6 +2972,8 @@ need_resched:
         rcu_note_context_switch(cpu);
         prev = rq->curr;
 
+        TS_SCHED_START;
+
         schedule_debug(prev);
 
         if (sched_feat(HRTICK))
@@ -3012,7 +3020,10 @@ need_resched:
                 rq->curr = next;
                 ++*switch_count;
 
+                TS_SCHED_END(next);
+                TS_CXS_START(next);
                 context_switch(rq, prev, next); /* unlocks the rq */
+                TS_CXS_END(current);
                 /*
                  * The context switch have flipped the stack from under us
                  * and restored the local variables which were saved when
@@ -3021,12 +3032,19 @@ need_resched:
                  */
                 cpu = smp_processor_id();
                 rq = cpu_rq(cpu);
-        } else
+        } else {
+                TS_SCHED_END(prev);
                 raw_spin_unlock_irq(&rq->lock);
+        }
+
+        TS_SCHED2_START(prev);
 
         post_schedule(rq);
 
         sched_preempt_enable_no_resched();
+
+        TS_SCHED2_END(prev);
+
         if (need_resched())
                 goto need_resched;
 }