perf: Add a timestamp to fork events

perf timechart needs to know when a process forked, in order to be
able to visualize properly when tasks start.

This patch adds a time field to the event structure, and fills it
in appropriately.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20090912130341.51ad2de2@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/linux/perf_counter.h

@@ -336,6 +336,7 @@ enum perf_event_type {
 	 *	struct perf_event_header	header;
 	 *	u32				pid, ppid;
 	 *	u32				tid, ptid;
+	 *	u64				time;
 	 * };
 	 */
 	PERF_EVENT_EXIT			= 4,
@@ -356,6 +357,7 @@ enum perf_event_type {
 	 *	struct perf_event_header	header;
 	 *	u32				pid, ppid;
 	 *	u32				tid, ptid;
+	 *	{ u64				time;     } && PERF_SAMPLE_TIME
 	 * };
 	 */
 	PERF_EVENT_FORK			= 7,

kernel/perf_counter.c

@@ -3083,16 +3083,20 @@ struct perf_task_event {
 		u32				ppid;
 		u32				tid;
 		u32				ptid;
+		u64				time;
 	} event;
 };
 
 static void perf_counter_task_output(struct perf_counter *counter,
 				     struct perf_task_event *task_event)
 {
 	struct perf_output_handle handle;
-	int size = task_event->event.header.size;
+	int size;
 	struct task_struct *task = task_event->task;
-	int ret = perf_output_begin(&handle, counter, size, 0, 0);
+	int ret;
+
+	size  = task_event->event.header.size;
+	ret = perf_output_begin(&handle, counter, size, 0, 0);
 
 	if (ret)
 		return;
@@ -3103,7 +3107,10 @@ static void perf_counter_task_output(struct perf_counter *counter,
 	task_event->event.tid = perf_counter_tid(counter, task);
 	task_event->event.ptid = perf_counter_tid(counter, current);
 
+	task_event->event.time = perf_clock();
+
 	perf_output_put(&handle, task_event->event);
+
 	perf_output_end(&handle);
 }
 

tools/perf/util/event.h

@@ -39,6 +39,7 @@ struct fork_event {
 	struct perf_event_header header;
 	u32 pid, ppid;
 	u32 tid, ptid;
+	u64 time;
 };
 
 struct lost_event {