perf data: Add support to store time of day in CTF data conversion

Adad support to convert and store time of day in CTF data conversion for
'perf data convert' subcommand.

The perf.data used for conversion needs to have clock data information -
must be recorded with -k/--clockid option).

New --tod option is added to 'perf data convert' subcommand to convert
data with timestamps converted to wall clock time.

Record data with clockid set:

# perf record -k CLOCK_MONOTONIC kill
kill: not enough arguments
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.033 MB perf.data (8 samples) ]

Convert data with TOD timestamps:

# perf data convert --tod --to-ctf ./ctf
[ perf data convert: Converted 'perf.data' into CTF data './ctf' ]
[ perf data convert: Converted and wrote 0.000 MB (8 samples) ]

Display data in perf script:

# perf script -F+tod --ns
perf 262150 2020-07-13 18:38:50.097678523 153633.958246159: 1 cycles: ...
perf 262150 2020-07-13 18:38:50.097682941 153633.958250577: 1 cycles: ...
perf 262150 2020-07-13 18:38:50.097684997 153633.958252633: 7 cycles: ...
...

Display data in babeltrace:

# babeltrace --clock-date ./ctf
[2020-07-13 18:38:50.097678523] (+?.?????????) cycles: { cpu_id = 0 }, { perf_ip = 0xFFF ...
[2020-07-13 18:38:50.097682941] (+0.000004418) cycles: { cpu_id = 0 }, { perf_ip = 0xFFF ...
[2020-07-13 18:38:50.097684997] (+0.000002056) cycles: { cpu_id = 0 }, { perf_ip = 0xFFF ...
...

It's available only for recording with clockid specified, because it's
the only case where we can get reference time to wallclock time. It's
can't do that with perf clock yet.

Error is display if you want to use --tod on data without clockid
specified:

# perf data convert --tod --to-ctf ./ctf
Can't provide --tod time, missing clock data. Please record with -k/--clockid option.
Failed to setup CTF writer.
Error during conversion setup.

Signed-off-by: Jiri Olsa <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Andi Kleen <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Geneviève Bastien <[e-mail]>
Cc: Ian Rogers <[e-mail]>
Cc: Jeremie Galarneau <[e-mail]>
Cc: Michael Petlan <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Wang Nan <[e-mail]>
Link: http://lore.kernel.org/lkml/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/Documentation/perf-data.txt

···
 --to-ctf::
 	Triggers the CTF conversion, specify the path of CTF data directory.
 
+--tod::
+	Convert time to wall clock time.
+
 -i::
 	Specify input perf data file path.
 

tools/perf/builtin-data.c

···
 		OPT_STRING('i', "input", &input_name, "file", "input file name"),
 #ifdef HAVE_LIBBABELTRACE_SUPPORT
 		OPT_STRING(0, "to-ctf", &to_ctf, NULL, "Convert to CTF format"),
+		OPT_BOOLEAN(0, "tod", &opts.tod, "Convert time to wall clock time"),
 #endif
 		OPT_BOOLEAN('f', "force", &opts.force, "don't complain, do it"),
 		OPT_BOOLEAN(0, "all", &opts.all, "Convert all events"),

tools/perf/util/data-convert-bt.c

···
 #include "config.h"
 #include <linux/ctype.h>
 #include <linux/err.h>
+#include <linux/time64.h>
+#include "util.h"
+#include "clockid.h"
 
 #define pr_N(n, fmt, ...) \
 	eprintf(n, debug_data_convert, fmt, ##__VA_ARGS__)
···
 	return 0;
 }
 
-static int ctf_writer__setup_clock(struct ctf_writer *cw)
+static int ctf_writer__setup_clock(struct ctf_writer *cw,
+				   struct perf_session *session,
+				   bool tod)
 {
 	struct bt_ctf_clock *clock = cw->clock;
+	const char *desc = "perf clock";
+	int64_t offset = 0;
 
-	bt_ctf_clock_set_description(clock, "perf clock");
+	if (tod) {
+		struct perf_env *env = &session->header.env;
+
+		if (!env->clock.enabled) {
+			pr_err("Can't provide --tod time, missing clock data. "
+			       "Please record with -k/--clockid option.\n");
+			return -1;
+		}
+
+		desc   = clockid_name(env->clock.clockid);
+		offset = env->clock.tod_ns - env->clock.clockid_ns;
+	}
 
 #define SET(__n, __v)				\
 do {						\
···
 } while (0)
 
 	SET(frequency,   1000000000);
-	SET(offset_s,    0);
-	SET(offset,      0);
+	SET(offset,      offset);
+	SET(description, desc);
 	SET(precision,   10);
 	SET(is_absolute, 0);
 
···
 	memset(cw, 0, sizeof(*cw));
 }
 
-static int ctf_writer__init(struct ctf_writer *cw, const char *path)
+static int ctf_writer__init(struct ctf_writer *cw, const char *path,
+			    struct perf_session *session, bool tod)
 {
 	struct bt_ctf_writer		*writer;
 	struct bt_ctf_stream_class	*stream_class;
···
 
 	cw->clock = clock;
 
-	if (ctf_writer__setup_clock(cw)) {
+	if (ctf_writer__setup_clock(cw, session, tod)) {
 		pr("Failed to setup CTF clock.\n");
 		goto err_cleanup;
 	}
···
 	if (err)
 		return err;
 
-	/* CTF writer */
-	if (ctf_writer__init(cw, path))
-		return -1;
-
 	err = -1;
 	/* perf.data session */
 	session = perf_session__new(&data, 0, &c.tool);
-	if (IS_ERR(session)) {
-		err = PTR_ERR(session);
-		goto free_writer;
-	}
+	if (IS_ERR(session))
+		return PTR_ERR(session);
+
+	/* CTF writer */
+	if (ctf_writer__init(cw, path, session, opts->tod))
+		goto free_session;
 
 	if (c.queue_size) {
 		ordered_events__set_alloc_size(&session->ordered_events,
···
 
 	/* CTF writer env/clock setup  */
 	if (ctf_writer__setup_env(cw, session))
-		goto free_session;
+		goto free_writer;
 
 	/* CTF events setup */
 	if (setup_events(cw, session))
-		goto free_session;
+		goto free_writer;
 
 	if (opts->all && setup_non_sample_events(cw, session))
-		goto free_session;
+		goto free_writer;
 
 	if (setup_streams(cw, session))
-		goto free_session;
+		goto free_writer;
 
 	err = perf_session__process_events(session);
 	if (!err)
···
 
 	return err;
 
-free_session:
-	perf_session__delete(session);
 free_writer:
 	ctf_writer__cleanup(cw);
+free_session:
+	perf_session__delete(session);
 	pr_err("Error during conversion setup.\n");
 	return err;
 }

tools/perf/util/data-convert.h

···
 struct perf_data_convert_opts {
 	bool force;
 	bool all;
+	bool tod;
 };
 
 #endif /* __DATA_CONVERT_H */