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>
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index c7375f9..bd34100 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -336,6 +336,7 @@
 	 *	struct perf_event_header	header;
 	 *	u32				pid, ppid;
 	 *	u32				tid, ptid;
+	 *	u64				time;
 	 * };
 	 */
 	PERF_EVENT_EXIT			= 4,
@@ -356,6 +357,7 @@
 	 *	struct perf_event_header	header;
 	 *	u32				pid, ppid;
 	 *	u32				tid, ptid;
+	 *	{ u64				time;     } && PERF_SAMPLE_TIME
 	 * };
 	 */
 	PERF_EVENT_FORK			= 7,