perf record: Add switch-output time option argument

It's now possible to specify the threshold time for perf.data like:

  $ perf record --switch-output=30s ...

Once it's reached, the current data are dumped in to the
perf.data.<timestamp> file and session does on.

  $ perf record --switch-output=30s ...
  [ perf record: dump data: Woken up 44 times ]
  [ perf record: Dump perf.data.2017010213043746 ]
  ...

The time is expected to be a number with appended unit
character - s/m/h/d.

Signed-off-by: Jiri Olsa <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Acked-by: Wang Nan <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: olsajiri

tools/perf/Documentation/perf-record.txt

@@ -427,6 +427,8 @@ based on 'mode' value:
   "signal" - when receiving a SIGUSR2 (default value) or
   <size>   - when reaching the size threshold, size is expected to
              be a number with appended unit character - B/K/M/G
+  <time>   - when reaching the time threshold, size is expected to
+             be a number with appended unit character - s/m/h/d
 
              Note: the precision of  the size  threshold  hugely depends
              on your configuration  - the number and size of  your  ring

tools/perf/builtin-record.c

@@ -50,6 +50,7 @@ struct switch_output {
 	bool		 enabled;
 	bool		 signal;
 	unsigned long	 size;
+	unsigned long	 time;
 	const char	*str;
 	bool		 set;
 };
@@ -91,6 +92,12 @@ static bool switch_output_size(struct record *rec)
 	       (rec->bytes_written >= rec->switch_output.size);
 }
 
+static bool switch_output_time(struct record *rec)
+{
+	return rec->switch_output.time &&
+	       trigger_is_ready(&switch_output_trigger);
+}
+
 static int record__write(struct record *rec, void *bf, size_t size)
 {
 	if (perf_data_file__write(rec->session->file, bf, size) < 0) {
@@ -737,6 +744,7 @@ static void workload_exec_failed_signal(int signo __maybe_unused,
 }
 
 static void snapshot_sig_handler(int sig);
+static void alarm_sig_handler(int sig);
 
 int __weak
 perf_event__synth_time_conv(const struct perf_event_mmap_page *pc __maybe_unused,
@@ -1068,6 +1076,10 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 				err = fd;
 				goto out_child;
 			}
+
+			/* re-arm the alarm */
+			if (rec->switch_output.time)
+				alarm(rec->switch_output.time);
 		}
 
 		if (hits == rec->samples) {
@@ -1404,6 +1416,13 @@ static int switch_output_setup(struct record *rec)
 		{ .tag  = 'G', .mult = 1 << 30 },
 		{ .tag  = 0 },
 	};
+	static struct parse_tag tags_time[] = {
+		{ .tag  = 's', .mult = 1        },
+		{ .tag  = 'm', .mult = 60       },
+		{ .tag  = 'h', .mult = 60*60    },
+		{ .tag  = 'd', .mult = 60*60*24 },
+		{ .tag  = 0 },
+	};
 	unsigned long val;
 
 	if (!s->set)
@@ -1422,6 +1441,14 @@ static int switch_output_setup(struct record *rec)
 		goto enabled;
 	}
 
+	val = parse_tag_value(s->str, tags_time);
+	if (val != (unsigned long) -1) {
+		s->time = val;
+		pr_debug("switch-output with %s time threshold (%lu seconds)\n",
+			 s->str, s->time);
+		goto enabled;
+	}
+
 	return -1;
 
 enabled:
@@ -1602,8 +1629,8 @@ static struct option __record_options[] = {
 	OPT_BOOLEAN(0, "timestamp-filename", &record.timestamp_filename,
 		    "append timestamp to output filename"),
 	OPT_STRING_OPTARG_SET(0, "switch-output", &record.switch_output.str,
-			  &record.switch_output.set, "signal,size",
-			  "Switch output when receive SIGUSR2 or cross size threshold",
+			  &record.switch_output.set, "signal,size,time",
+			  "Switch output when receive SIGUSR2 or cross size,time threshold",
 			  "signal"),
 	OPT_BOOLEAN(0, "dry-run", &dry_run,
 		    "Parse options then exit"),
@@ -1667,6 +1694,11 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused)
 		return -EINVAL;
 	}
 
+	if (rec->switch_output.time) {
+		signal(SIGALRM, alarm_sig_handler);
+		alarm(rec->switch_output.time);
+	}
+
 	if (!rec->itr) {
 		rec->itr = auxtrace_record__init(rec->evlist, &err);
 		if (err)
@@ -1819,3 +1851,11 @@ static void snapshot_sig_handler(int sig __maybe_unused)
 	if (switch_output_signal(rec))
 		trigger_hit(&switch_output_trigger);
 }
+
+static void alarm_sig_handler(int sig __maybe_unused)
+{
+	struct record *rec = &record;
+
+	if (switch_output_time(rec))
+		trigger_hit(&switch_output_trigger);
+}