perf daemon: Add up time for daemon/session list

Display up time for both daemon and sessions.

Example:

# cat ~/.perfconfig
[daemon]
base=/opt/perfdata

[session-cycles]
run = -m 10M -e cycles --overwrite --switch-output -a

[session-sched]
run = -m 20M -e sched:* --overwrite --switch-output -a

Starting the daemon:

# perf daemon start

Get the details with up time:

# perf daemon -v
[778315:daemon] base: /opt/perfdata
output: /opt/perfdata/output
lock: /opt/perfdata/lock
up: 15 minutes
[778316:cycles] perf record -m 20M -e cycles --overwrite --switch-output -a
base: /opt/perfdata/session-cycles
output: /opt/perfdata/session-cycles/output
control: /opt/perfdata/session-cycles/control
ack: /opt/perfdata/session-cycles/ack
up: 10 minutes
[778317:sched] perf record -m 20M -e sched:* --overwrite --switch-output -a
base: /opt/perfdata/session-sched
output: /opt/perfdata/session-sched/output
control: /opt/perfdata/session-sched/control
ack: /opt/perfdata/session-sched/ack
up: 2 minutes

Signed-off-by: Jiri Olsa <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Alexei Budankov <[e-mail]>
Cc: Ian Rogers <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Michael Petlan <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/builtin-daemon.c

···
 #include <sys/wait.h>
 #include <poll.h>
 #include <sys/stat.h>
+#include <time.h>
 #include "builtin.h"
 #include "perf.h"
 #include "debug.h"
···
 	int				 pid;
 	struct list_head		 list;
 	enum daemon_session_state	 state;
+	time_t				 start;
 };
 
 struct daemon {
···
 	FILE			*out;
 	char			 perf[PATH_MAX];
 	int			 signal_fd;
+	time_t			 start;
 };
 
 static struct daemon __daemon = {
···
 		perror("failed: mkdir");
 		return -1;
 	}
+
+	session->start = time(NULL);
 
 	session->pid = fork();
 	if (session->pid < 0)
···
 {
 	char csv_sep = cmd->list.csv_sep;
 	struct daemon_session *session;
+	time_t curr = time(NULL);
 
 	if (csv_sep) {
 		fprintf(out, "%d%c%s%c%s%c%s/%s",
···
 			/* lock */
 			csv_sep, daemon->base, "lock");
 
+		fprintf(out, "%c%lu",
+			/* session up time */
+			csv_sep, (curr - daemon->start) / 60);
+
 		fprintf(out, "\n");
 	} else {
 		fprintf(out, "[%d:daemon] base: %s\n", getpid(), daemon->base);
···
 				daemon->base, SESSION_OUTPUT);
 			fprintf(out, "  lock:    %s/lock\n",
 				daemon->base);
+			fprintf(out, "  up:      %lu minutes\n",
+				(curr - daemon->start) / 60);
 		}
 	}
 
···
 				/* session ack */
 				csv_sep, session->base, SESSION_ACK);
 
+			fprintf(out, "%c%lu",
+				/* session up time */
+				csv_sep, (curr - session->start) / 60);
+
 			fprintf(out, "\n");
 		} else {
 			fprintf(out, "[%d:%s] perf record %s\n",
···
 				session->base, SESSION_CONTROL);
 			fprintf(out, "  ack:     %s/%s\n",
 				session->base, SESSION_ACK);
+			fprintf(out, "  up:      %lu minutes\n",
+				(curr - session->start) / 60);
 		}
 	}
 
···
 	argc = parse_options(argc, argv, start_options, daemon_usage, 0);
 	if (argc)
 		usage_with_options(daemon_usage, start_options);
+
+	daemon->start = time(NULL);
 
 	if (setup_config(daemon)) {
 		pr_err("failed: config not found\n");