Import TRACE_EVENT macro from the kernel v3

[ust.git] / include / ust / tracepoint.h

diff --git a/include/ust/tracepoint.h b/include/ust/tracepoint.h
index be35f92665e7d69eeaf6633f95c535c213262c9b..1a91b79ff526fab81d1b09a9cc256b2dd99ac02b 100644 (file)
--- a/include/ust/tracepoint.h
+++ b/include/ust/tracepoint.h
@@ -4,6 +4,7 @@
 /*
  * Copyright (C) 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
  * Copyright (C) 2009 Pierre-Marc Fournier
+ * Copyright (C) 2009 Steven Rostedt <rostedt@goodmis.org>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -43,6 +44,8 @@ struct tracepoint {
                                         * Keep in sync with vmlinux.lds.h.
                                         */
 
+#define PARAMS(args...) args
+
 #define TP_PROTO(args...)      args
 #define TP_ARGS(args...)       args
 
@@ -206,4 +209,121 @@ extern int tracepoint_unregister_lib(struct tracepoint *tracepoints_start);
                tracepoint_unregister_lib(__start___tracepoints); \
        }
 
+
+#ifndef TRACE_EVENT
+/*
+ * For use with the TRACE_EVENT macro:
+ *
+ * We define a tracepoint, its arguments, its printf format
+ * and its 'fast binary record' layout.
+ *
+ * Firstly, name your tracepoint via TRACE_EVENT(name : the
+ * 'subsystem_event' notation is fine.
+ *
+ * Think about this whole construct as the
+ * 'trace_sched_switch() function' from now on.
+ *
+ *
+ *  TRACE_EVENT(sched_switch,
+ *
+ *     *
+ *     * A function has a regular function arguments
+ *     * prototype, declare it via TP_PROTO():
+ *     *
+ *
+ *     TP_PROTO(struct rq *rq, struct task_struct *prev,
+ *              struct task_struct *next),
+ *
+ *     *
+ *     * Define the call signature of the 'function'.
+ *     * (Design sidenote: we use this instead of a
+ *     *  TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
+ *     *
+ *
+ *     TP_ARGS(rq, prev, next),
+ *
+ *     *
+ *     * Fast binary tracing: define the trace record via
+ *     * TP_STRUCT__entry(). You can think about it like a
+ *     * regular C structure local variable definition.
+ *     *
+ *     * This is how the trace record is structured and will
+ *     * be saved into the ring buffer. These are the fields
+ *     * that will be exposed to readers.
+ *     *
+ *     * The declared 'local variable' is called '__entry'
+ *     *
+ *     * __field(pid_t, prev_prid) is equivalent to a standard declariton:
+ *     *
+ *     *       pid_t   prev_pid;
+ *     *
+ *     * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to:
+ *     *
+ *     *       char    prev_comm[TASK_COMM_LEN];
+ *     *
+ *
+ *     TP_STRUCT__entry(
+ *             __array(        char,   prev_comm,      TASK_COMM_LEN   )
+ *             __field(        pid_t,  prev_pid                        )
+ *             __field(        int,    prev_prio                       )
+ *             __array(        char,   next_comm,      TASK_COMM_LEN   )
+ *             __field(        pid_t,  next_pid                        )
+ *             __field(        int,    next_prio                       )
+ *     ),
+ *
+ *     *
+ *     * Assign the entry into the trace record, by embedding
+ *     * a full C statement block into TP_fast_assign(). You
+ *     * can refer to the trace record as '__entry' -
+ *     * otherwise you can put arbitrary C code in here.
+ *     *
+ *     * Note: this C code will execute every time a trace event
+ *     * happens, on an active tracepoint.
+ *     *
+ *
+ *     TP_fast_assign(
+ *             memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
+ *             __entry->prev_pid       = prev->pid;
+ *             __entry->prev_prio      = prev->prio;
+ *             memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
+ *             __entry->next_pid       = next->pid;
+ *             __entry->next_prio      = next->prio;
+ *     )
+ *
+ *     *
+ *     * Formatted output of a trace record via TP_printf().
+ *     * This is how the tracepoint will appear under debugging
+ *     * of tracepoints.
+ *     *
+ *     * (raw-binary tracing wont actually perform this step.)
+ *     *
+ *
+ *     TP_printf("task %s:%d [%d] ==> %s:%d [%d]",
+ *             __entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
+ *             __entry->next_comm, __entry->next_pid, __entry->next_prio),
+ *
+ * );
+ *
+ * This macro construct is thus used for the regular printf format
+ * tracing setup.
+ *
+ * A set of (un)registration functions can be passed to the variant
+ * TRACE_EVENT_FN to perform any (un)registration work.
+ */
+
+#define DECLARE_TRACE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
+#define DEFINE_TRACE_EVENT(template, name, proto, args)                \
+       DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
+#define DEFINE_TRACE_EVENT_PRINT(template, name, proto, args, print)   \
+       DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
+
+#define TRACE_EVENT(name, proto, args, struct, assign, print)  \
+       DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
+#define TRACE_EVENT_FN(name, proto, args, struct,              \
+               assign, print, reg, unreg)                      \
+       DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
+
+#endif /* ifdef TRACE_EVENT (see note above) */
+
+
 #endif /* _UST_TRACEPOINT_H */