Add tracepoint support

This patch integrates LITMUS^RT's sched_trace_XXX() macros with
Linux's notion of tracepoints. This is useful to visualize schedules
in kernel shark and similar tools. Historically, LITMUS^RT's
sched_trace predates Linux's tracepoint infrastructure.

2 files changed, 22 insertions, 0 deletions

diff --git a/litmus/Kconfig b/litmus/Kconfig
index 19211ac1320a..5408ef6b159b 100644
--- a/litmus/Kconfig
+++ b/litmus/Kconfig
@@ -58,6 +58,24 @@ config SCHED_TASK_TRACE_SHIFT
                    10 =>   1k events
                     8 =>  512 events
 
+config SCHED_LITMUS_TRACEPOINT
+        bool "Enable Event/Tracepoint Tracing for real-time task tracing"
+        depends on TRACEPOINTS
+        default n
+        help
+          Enable kernel-style events (tracepoint) for Litmus. Litmus events
+          trace the same functions as the above sched_trace_XXX(), but can
+          be enabled independently.
+          Litmus tracepoints can be recorded and analyzed together (single
+          time reference) with all other kernel tracing events (e.g.,
+          sched:sched_switch, etc.).
+
+          This also enables a quick way to visualize schedule traces using
+          trace-cmd utility and kernelshark visualizer.
+
+          Say Yes for debugging and visualization purposes.
+          Say No for overhead tracing.
+
 config SCHED_OVERHEAD_TRACE
         bool "Record timestamps for overhead measurements"
         depends on FEATHER_TRACE
diff --git a/litmus/sched_task_trace.c b/litmus/sched_task_trace.c
index 4f95551df1b4..fb4eddf1d7bc 100644
--- a/litmus/sched_task_trace.c
+++ b/litmus/sched_task_trace.c
@@ -15,6 +15,10 @@
 #include <litmus/feather_trace.h>
 #include <litmus/ftdev.h>
 
+#ifdef CONFIG_SCHED_LITMUS_TRACEPOINT
+#define CREATE_TRACE_POINTS
+#include <trace/events/litmus.h>
+#endif
 
 #define NO_EVENTS               (1 << CONFIG_SCHED_TASK_TRACE_SHIFT)