perf trace: Add option to show full timestamp

Current timestamp shown for output is time relative to firt sample. This
patch adds an option to show the absolute perf_clock timestamp which is
useful when comparing output across commands (e.g., perf-trace to
perf-script).

Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1378319865-55695-1-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-trace.txt

@@ -78,6 +78,10 @@ the thread executes on the designated CPUs. Default is to monitor all CPUs.
 --input
 	Process events from a given perf data file.
 
+-T
+--time
+	Print full timestamp rather time relative to first sample.
+
 SEE ALSO
 --------
 linkperf:perf-record[1], linkperf:perf-script[1]

tools/perf/builtin-trace.c

@@ -624,6 +624,7 @@ struct trace {
 	struct perf_record_opts opts;
 	struct machine		host;
 	u64			base_time;
+	bool			full_time;
 	FILE			*output;
 	unsigned long		nr_events;
 	struct strlist		*ev_qualifier;
@@ -1066,7 +1067,7 @@ static int trace__process_sample(struct perf_tool *tool,
 	if (skip_sample(trace, sample))
 		return 0;
 
-	if (trace->base_time == 0)
+	if (!trace->full_time && trace->base_time == 0)
 		trace->base_time = sample->time;
 
 	if (handler)
@@ -1195,7 +1196,7 @@ again:
 				continue;
 			}
 
-			if (trace->base_time == 0)
+			if (!trace->full_time && trace->base_time == 0)
 				trace->base_time = sample.time;
 
 			if (type != PERF_RECORD_SAMPLE) {
@@ -1433,6 +1434,8 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
 		     trace__set_duration),
 	OPT_BOOLEAN(0, "sched", &trace.sched, "show blocking scheduler events"),
 	OPT_INCR('v', "verbose", &verbose, "be more verbose"),
+	OPT_BOOLEAN('T', "time", &trace.full_time,
+		    "Show full timestamp, not time relative to first start"),
 	OPT_END()
 	};
 	int err;