[PATCH v2 2/6] perf record: Split output into multiple files via '--switch-output'

[Wang Nan]

Allow 'perf record' splits its output into multiple files.

For example:

 # ~/perf record -a --timestamp-filename --switch-output &
 [1] 10763
 # kill -s SIGUSR2 10763
 [ perf record: dump data: Woken up 1 times ]
 # [ perf record: Dump perf.data.2015122622314468 ]

 # kill -s SIGUSR2 10763
 [ perf record: dump data: Woken up 1 times ]
 # [ perf record: Dump perf.data.2015122622314762 ]

 # kill -s SIGUSR2 10763
 [ perf record: dump data: Woken up 1 times ]
 #[ perf record: Dump perf.data.2015122622315171 ]

 # fg
 perf record -a --timestamp-filename --switch-output
 ^C[ perf record: Woken up 1 times to write data ]
 [ perf record: Dump perf.data.2015122622315513 ]
 [ perf record: Captured and wrote 0.014 MB perf.data.<timestamp> (296 samples) ]

 # ls -l
 total 920
 -rw------- 1 root root 797692 Dec 26 22:31 perf.data.2015122622314468
 -rw------- 1 root root  59960 Dec 26 22:31 perf.data.2015122622314762
 -rw------- 1 root root  59912 Dec 26 22:31 perf.data.2015122622315171
 -rw------- 1 root root  19220 Dec 26 22:31 perf.data.2015122622315513

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Signed-off-by: He Kuang <hekuang@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
---
 tools/perf/builtin-record.c | 41 ++++++++++++++++++++++++++++++++++-------
 tools/perf/util/util.h      | 11 ++++++++++-
 2 files changed, 44 insertions(+), 8 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 13fe9a6..ca40726 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -57,6 +57,7 @@ struct record {
 	bool			no_buildid_cache_set;
 	bool			buildid_all;
 	bool			timestamp_filename;
+	bool			switch_output;
 	unsigned long long	samples;
 };
 
@@ -131,6 +132,8 @@ static DEFINE_TRIGGER(auxtrace_snapshot, OFF);
 static volatile int auxtrace_snapshot_err;
 static volatile int auxtrace_record__snapshot_started;
 
+static DEFINE_TRIGGER(switch_output, OFF);
+
 static void sig_handler(int sig)
 {
 	if (sig == SIGCHLD)
@@ -649,9 +652,12 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 	signal(SIGINT, sig_handler);
 	signal(SIGTERM, sig_handler);
 
-	if (rec->opts.auxtrace_snapshot_mode) {
+	if (rec->opts.auxtrace_snapshot_mode || rec->switch_output) {
 		signal(SIGUSR2, snapshot_sig_handler);
-		auxtrace_snapshot_on();
+		if (rec->opts.auxtrace_snapshot_mode)
+			auxtrace_snapshot_on();
+		if (rec->switch_output)
+			switch_output_on();
 	} else {
 		signal(SIGUSR2, SIG_IGN);
 	}
@@ -781,6 +787,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 	}
 
 	auxtrace_snapshot_enable();
+	switch_output_enable();
 	for (;;) {
 		unsigned long long hits = rec->samples;
 
@@ -801,6 +808,21 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 			}
 		}
 
+		if (switch_output_is_disabled()) {
+			switch_output_enable();
+
+			if (!quiet)
+				fprintf(stderr, "[ perf record: dump data: Woken up %ld times ]\n",
+					waking);
+			waking = 0;
+			fd = record__switch_output(rec, false);
+			if (fd < 0) {
+				pr_err("Failed to switch to new file\n");
+				err = fd;
+				goto out_child;
+			}
+		}
+
 		if (hits == rec->samples) {
 			if (done || draining)
 				break;
@@ -1259,6 +1281,8 @@ struct option __record_options[] = {
 		    "Record build-id of all DSOs regardless of hits"),
 	OPT_BOOLEAN(0, "timestamp-filename", &record.timestamp_filename,
 		    "append timestamp to output filename"),
+	OPT_BOOLEAN(0, "switch-output", &record.switch_output,
+		    "Switch output when receive SIGUSR2"),
 	OPT_END()
 };
 
@@ -1407,9 +1431,12 @@ out_symbol_exit:
 
 static void snapshot_sig_handler(int sig __maybe_unused)
 {
-	if (!auxtrace_snapshot_is_enabled())
-		return;
-	auxtrace_snapshot_disable();
-	auxtrace_snapshot_err = auxtrace_record__snapshot_start(record.itr);
-	auxtrace_record__snapshot_started = 1;
+	if (auxtrace_snapshot_is_enabled()) {
+		auxtrace_snapshot_disable();
+		auxtrace_snapshot_err = auxtrace_record__snapshot_start(record.itr);
+		auxtrace_record__snapshot_started = 1;
+	}
+
+	if (switch_output_is_enabled())
+		switch_output_disable();
 }
diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index 8121029..46bf35b 100644
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -398,6 +398,14 @@ trigger_is_enabled(struct trigger *s)
 	return false;
 }
 
+static inline bool
+trigger_is_disabled(struct trigger *s)
+{
+	if (s->state != TRIGGER_OFF)
+		return s->state == TRIGGER_DISABLED;
+	return false;
+}
+
 #define __TRIGGER_VAR(n) n##_state
 #define __DEF_TRIGGER_VOID_FUNC(n, op)	\
 static inline void n##_##op(void) {trigger_##op(&__TRIGGER_VAR(n)); }
@@ -410,6 +418,7 @@ struct trigger n##_state = {.state = TRIGGER_##def};\
 __DEF_TRIGGER_VOID_FUNC(n, on)				\
 __DEF_TRIGGER_VOID_FUNC(n, enable)			\
 __DEF_TRIGGER_VOID_FUNC(n, disable)			\
-__DEF_TRIGGER_FUNC(n, bool, is_enabled)
+__DEF_TRIGGER_FUNC(n, bool, is_enabled)			\
+__DEF_TRIGGER_FUNC(n, bool, is_disabled)
 
 #endif /* GIT_COMPAT_UTIL_H */
-- 
1.8.3.4