Feather-Trace: add LITMUS^RT overhead tracing infrastructure

This patch adds the main infrastructure for tracing overheads in
LITMUS^RT.  It does not yet introduce any tracepoints into the kernel.

1 files changed, 137 insertions, 0 deletions

diff --git a/include/litmus/trace.h b/include/litmus/trace.h
new file mode 100644
index 000000000000..489b3d84f880
--- /dev/null
+++ b/include/litmus/trace.h
@@ -0,0 +1,137 @@
+#ifndef _SYS_TRACE_H_
+#define _SYS_TRACE_H_
+
+#ifdef CONFIG_SCHED_OVERHEAD_TRACE
+
+
+#include <litmus/feather_trace.h>
+#include <litmus/feather_buffer.h>
+
+
+/*********************** TIMESTAMPS ************************/
+
+enum task_type_marker {
+        TSK_BE,
+        TSK_RT,
+        TSK_UNKNOWN
+};
+
+struct timestamp {
+        uint64_t                timestamp:48;
+        uint64_t                pid:16;
+        uint32_t                seq_no;
+        uint8_t                 cpu;
+        uint8_t                 event;
+        uint8_t                 task_type:2;
+        uint8_t                 irq_flag:1;
+        uint8_t                 irq_count:5;
+};
+
+/* tracing callbacks */
+feather_callback void save_timestamp(unsigned long event);
+feather_callback void save_timestamp_def(unsigned long event, unsigned long type);
+feather_callback void save_timestamp_task(unsigned long event, unsigned long t_ptr);
+feather_callback void save_timestamp_cpu(unsigned long event, unsigned long cpu);
+feather_callback void save_timestamp_time(unsigned long event, unsigned long time_ptr);
+feather_callback void save_timestamp_irq(unsigned long event, unsigned long irq_count_ptr);
+feather_callback void save_timestamp_hide_irq(unsigned long event);
+
+#define TIMESTAMP(id) ft_event0(id, save_timestamp)
+
+#define DTIMESTAMP(id, def)  ft_event1(id, save_timestamp_def, (unsigned long) def)
+
+#define TIMESTAMP_CUR(id) DTIMESTAMP(id, is_realtime(current) ? TSK_RT : TSK_BE)
+
+#define TTIMESTAMP(id, task) \
+        ft_event1(id, save_timestamp_task, (unsigned long) task)
+
+#define CTIMESTAMP(id, cpu) \
+        ft_event1(id, save_timestamp_cpu, (unsigned long) cpu)
+
+#define TIMESTAMP_TIME(id, time_ptr) \
+        ft_event1(id, save_timestamp_time, (unsigned long) time_ptr)
+
+#define TIMESTAMP_IRQ(id, irq_count_ptr) \
+        ft_event1(id, save_timestamp_irq, (unsigned long) irq_count_ptr)
+
+#define TIMESTAMP_IN_IRQ(id) \
+        ft_event0(id, save_timestamp_hide_irq)
+
+#else /* !CONFIG_SCHED_OVERHEAD_TRACE */
+
+#define TIMESTAMP(id)        /* no tracing */
+
+#define DTIMESTAMP(id, def)  /* no tracing */
+
+#define TIMESTAMP_CUR(id)    /* no tracing */
+
+#define TTIMESTAMP(id, task) /* no tracing */
+
+#define CTIMESTAMP(id, cpu)  /* no tracing */
+
+#define TIMESTAMP_TIME(id, time_ptr) /* no tracing */
+
+#define TIMESTAMP_IRQ(id, irq_count_ptr) /* no tracing */
+
+#define TIMESTAMP_IN_IRQ(id) /* no tracing */
+
+#endif
+
+
+/* Convention for timestamps
+ * =========================
+ *
+ * In order to process the trace files with a common tool, we use the following
+ * convention to measure execution times: The end time id of a code segment is
+ * always the next number after the start time event id.
+ */
+
+#define __TS_SYSCALL_IN_START(p)        TIMESTAMP_TIME(10, p)
+#define __TS_SYSCALL_IN_END(p)          TIMESTAMP_IRQ(11, p)
+
+#define TS_SYSCALL_OUT_START            TIMESTAMP_CUR(20)
+#define TS_SYSCALL_OUT_END              TIMESTAMP_CUR(21)
+
+#define TS_LOCK_START                   TIMESTAMP_CUR(30)
+#define TS_LOCK_END                     TIMESTAMP_CUR(31)
+
+#define TS_LOCK_SUSPEND                 TIMESTAMP_CUR(38)
+#define TS_LOCK_RESUME                  TIMESTAMP_CUR(39)
+
+#define TS_UNLOCK_START                 TIMESTAMP_CUR(40)
+#define TS_UNLOCK_END                   TIMESTAMP_CUR(41)
+
+#define TS_SCHED_START                  DTIMESTAMP(100, TSK_UNKNOWN) /* we only
+                                                                      * care
+                                                                      * about
+                                                                      * next */
+#define TS_SCHED_END(t)                 TTIMESTAMP(101, t)
+#define TS_SCHED2_START(t)              TTIMESTAMP(102, t)
+#define TS_SCHED2_END(t)                TTIMESTAMP(103, t)
+
+#define TS_CXS_START(t)                 TTIMESTAMP(104, t)
+#define TS_CXS_END(t)                   TTIMESTAMP(105, t)
+
+#define TS_RELEASE_START                DTIMESTAMP(106, TSK_RT)
+#define TS_RELEASE_END                  DTIMESTAMP(107, TSK_RT)
+
+#define TS_TICK_START(t)                TTIMESTAMP(110, t)
+#define TS_TICK_END(t)                  TTIMESTAMP(111, t)
+
+
+#define TS_PLUGIN_SCHED_START           /* TIMESTAMP(120) */  /* currently unused */
+#define TS_PLUGIN_SCHED_END             /* TIMESTAMP(121) */
+
+#define TS_PLUGIN_TICK_START            /* TIMESTAMP(130) */
+#define TS_PLUGIN_TICK_END              /* TIMESTAMP(131) */
+
+#define TS_ENTER_NP_START               TIMESTAMP(140)
+#define TS_ENTER_NP_END                 TIMESTAMP(141)
+
+#define TS_EXIT_NP_START                TIMESTAMP(150)
+#define TS_EXIT_NP_END                  TIMESTAMP(151)
+
+#define TS_SEND_RESCHED_START(c)        CTIMESTAMP(190, c)
+#define TS_SEND_RESCHED_END             TIMESTAMP_IN_IRQ(191)
+
+#endif /* !_SYS_TRACE_H_ */