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.

4 files changed, 261 insertions, 0 deletions

diff --git a/include/litmus/sched_trace.h b/include/litmus/sched_trace.h
index 589c63a142b5..0532424fbee6 100644
--- a/include/litmus/sched_trace.h
+++ b/include/litmus/sched_trace.h
@@ -196,24 +196,28 @@ feather_callback void do_sched_trace_sys_release(unsigned long id,
         do {                                                            \
                 SCHED_TRACE(SCHED_TRACE_BASE_ID + 2,                    \
                                 do_sched_trace_task_param, t);          \
+                trace_litmus_task_param(t);                             \
         } while (0)
 
 #define sched_trace_task_release(t)                                     \
         do {                                                            \
                 SCHED_TRACE(SCHED_TRACE_BASE_ID + 3,                    \
                                 do_sched_trace_task_release, t);        \
+                trace_litmus_task_release(t);                           \
         } while (0)
 
 #define sched_trace_task_switch_to(t)                                   \
         do {                                                            \
                 SCHED_TRACE(SCHED_TRACE_BASE_ID + 4,                    \
                         do_sched_trace_task_switch_to, t);              \
+                trace_litmus_switch_to(t);                              \
         } while (0)
 
 #define sched_trace_task_switch_away(t)                                 \
         do {                                                            \
                 SCHED_TRACE(SCHED_TRACE_BASE_ID + 5,                    \
                         do_sched_trace_task_switch_away, t);            \
+                trace_litmus_switch_away(t);                            \
         } while (0)
 
 #define sched_trace_task_completion(t, forced)                          \
@@ -221,18 +225,21 @@ feather_callback void do_sched_trace_sys_release(unsigned long id,
                 SCHED_TRACE2(SCHED_TRACE_BASE_ID + 6,                   \
                                 do_sched_trace_task_completion, t,      \
                                 (unsigned long) forced);                \
+                trace_litmus_task_completion(t, forced);                \
         } while (0)
 
 #define sched_trace_task_block(t)                                       \
         do {                                                            \
                 SCHED_TRACE(SCHED_TRACE_BASE_ID + 7,                    \
                         do_sched_trace_task_block, t);                  \
+                trace_litmus_task_block(t);                             \
         } while (0)
 
 #define sched_trace_task_resume(t)                                      \
         do {                                                            \
                 SCHED_TRACE(SCHED_TRACE_BASE_ID + 8,                    \
                                 do_sched_trace_task_resume, t);         \
+                trace_litmus_task_resume(t);                            \
         } while (0)
 
 #define sched_trace_action(t, action)                                   \
@@ -244,6 +251,7 @@ feather_callback void do_sched_trace_sys_release(unsigned long id,
         do {                                                            \
                 SCHED_TRACE(SCHED_TRACE_BASE_ID + 10,                   \
                         do_sched_trace_sys_release, when);              \
+                trace_litmus_sys_release(when);                         \
         } while (0)
 
 #define sched_trace_last_suspension_as_completion(t)    \
diff --git a/include/trace/events/litmus.h b/include/trace/events/litmus.h
new file mode 100644
index 000000000000..0fffcee02be0
--- /dev/null
+++ b/include/trace/events/litmus.h
@@ -0,0 +1,231 @@
+/*
+ * LITMUS^RT kernel style scheduling tracepoints
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM litmus
+
+#if !defined(_SCHED_TASK_TRACEPOINT_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _SCHED_TASK_TRACEPOINT_H
+
+#include <linux/tracepoint.h>
+
+#include <litmus/litmus.h>
+#include <litmus/rt_param.h>
+
+/*
+ * Tracing task admission
+ */
+TRACE_EVENT(litmus_task_param,
+
+        TP_PROTO(struct task_struct *t),
+
+        TP_ARGS(t),
+
+        TP_STRUCT__entry(
+                __field( pid_t,         pid     )
+                __field( unsigned int,  job     )
+                __field( lt_t,          wcet    )
+                __field( lt_t,          period  )
+                __field( lt_t,          phase   )
+                __field( int,           partition )
+        ),
+
+        TP_fast_assign(
+                __entry->pid    = t ? t->pid : 0;
+                __entry->job    = t ? t->rt_param.job_params.job_no : 0;
+                __entry->wcet   = get_exec_cost(t);
+                __entry->period = get_rt_period(t);
+                __entry->phase  = get_rt_phase(t);
+                __entry->partition = get_partition(t);
+        ),
+
+        TP_printk("period(%d, %Lu).\nwcet(%d, %Lu).\n",
+                __entry->pid, __entry->period,
+                __entry->pid, __entry->wcet)
+);
+
+/*
+ * Tracing jobs release
+ */
+TRACE_EVENT(litmus_task_release,
+
+        TP_PROTO(struct task_struct *t),
+
+        TP_ARGS(t),
+
+        TP_STRUCT__entry(
+                __field( pid_t,         pid     )
+                __field( unsigned int,  job     )
+                __field( lt_t,          release )
+                __field( lt_t,          deadline        )
+        ),
+
+        TP_fast_assign(
+                __entry->pid    = t ? t->pid : 0;
+                __entry->job    = t ? t->rt_param.job_params.job_no : 0;
+                __entry->release        = get_release(t);
+                __entry->deadline       = get_deadline(t);
+        ),
+
+        TP_printk("release(job(%u, %u)): %Lu\ndeadline(job(%u, %u)): %Lu\n",
+                        __entry->pid, __entry->job, __entry->release,
+                        __entry->pid, __entry->job, __entry->deadline)
+);
+
+/*
+ * Tracepoint for switching to new task
+ */
+TRACE_EVENT(litmus_switch_to,
+
+        TP_PROTO(struct task_struct *t),
+
+        TP_ARGS(t),
+
+        TP_STRUCT__entry(
+                __field( pid_t,         pid     )
+                __field( unsigned int,  job     )
+                __field( lt_t,          when    )
+                __field( lt_t,          exec_time       )
+        ),
+
+        TP_fast_assign(
+                __entry->pid    = is_realtime(t) ? t->pid : 0;
+                __entry->job    = is_realtime(t) ? t->rt_param.job_params.job_no : 0;
+                __entry->when           = litmus_clock();
+                __entry->exec_time      = get_exec_time(t);
+        ),
+
+        TP_printk("switch_to(job(%u, %u)): %Lu (exec: %Lu)\n",
+                        __entry->pid, __entry->job,
+                        __entry->when, __entry->exec_time)
+);
+
+/*
+ * Tracepoint for switching away previous task
+ */
+TRACE_EVENT(litmus_switch_away,
+
+        TP_PROTO(struct task_struct *t),
+
+        TP_ARGS(t),
+
+        TP_STRUCT__entry(
+                __field( pid_t,         pid     )
+                __field( unsigned int,  job     )
+                __field( lt_t,          when    )
+                __field( lt_t,          exec_time       )
+        ),
+
+        TP_fast_assign(
+                __entry->pid    = is_realtime(t) ? t->pid : 0;
+                __entry->job    = is_realtime(t) ? t->rt_param.job_params.job_no : 0;
+                __entry->when           = litmus_clock();
+                __entry->exec_time      = get_exec_time(t);
+        ),
+
+        TP_printk("switch_away(job(%u, %u)): %Lu (exec: %Lu)\n",
+                        __entry->pid, __entry->job,
+                        __entry->when, __entry->exec_time)
+);
+
+/*
+ * Tracing jobs completion
+ */
+TRACE_EVENT(litmus_task_completion,
+
+        TP_PROTO(struct task_struct *t, unsigned long forced),
+
+        TP_ARGS(t, forced),
+
+        TP_STRUCT__entry(
+                __field( pid_t,         pid     )
+                __field( unsigned int,  job     )
+                __field( lt_t,          when    )
+                __field( unsigned long, forced  )
+        ),
+
+        TP_fast_assign(
+                __entry->pid    = t ? t->pid : 0;
+                __entry->job    = t ? t->rt_param.job_params.job_no : 0;
+                __entry->when   = litmus_clock();
+                __entry->forced = forced;
+        ),
+
+        TP_printk("completed(job(%u, %u)): %Lu (forced: %lu)\n",
+                        __entry->pid, __entry->job,
+                        __entry->when, __entry->forced)
+);
+
+/*
+ * Trace blocking tasks.
+ */
+TRACE_EVENT(litmus_task_block,
+
+        TP_PROTO(struct task_struct *t),
+
+        TP_ARGS(t),
+
+        TP_STRUCT__entry(
+                __field( pid_t,         pid     )
+                __field( lt_t,          when    )
+        ),
+
+        TP_fast_assign(
+                __entry->pid    = t ? t->pid : 0;
+                __entry->when   = litmus_clock();
+        ),
+
+        TP_printk("(%u) blocks: %Lu\n", __entry->pid, __entry->when)
+);
+
+/*
+ * Tracing jobs resume
+ */
+TRACE_EVENT(litmus_task_resume,
+
+        TP_PROTO(struct task_struct *t),
+
+        TP_ARGS(t),
+
+        TP_STRUCT__entry(
+                __field( pid_t,         pid     )
+                __field( unsigned int,  job     )
+                __field( lt_t,          when    )
+        ),
+
+        TP_fast_assign(
+                __entry->pid    = t ? t->pid : 0;
+                __entry->job    = t ? t->rt_param.job_params.job_no : 0;
+                __entry->when   = litmus_clock();
+        ),
+
+        TP_printk("resume(job(%u, %u)): %Lu\n",
+                        __entry->pid, __entry->job, __entry->when)
+);
+
+/*
+ * Trace synchronous release
+ */
+TRACE_EVENT(litmus_sys_release,
+
+        TP_PROTO(lt_t *start),
+
+        TP_ARGS(start),
+
+        TP_STRUCT__entry(
+                __field( lt_t,          rel     )
+                __field( lt_t,          when    )
+        ),
+
+        TP_fast_assign(
+                __entry->rel    = *start;
+                __entry->when   = litmus_clock();
+        ),
+
+        TP_printk("SynRelease(%Lu) at %Lu\n", __entry->rel, __entry->when)
+);
+
+#endif /* _SCHED_TASK_TRACEPOINT_H */
+
+/* Must stay outside the protection */
+#include <trace/define_trace.h>
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 cfbc1c77383a..f89d08405944 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)