data-convert-bt.c

/*
 * CTF writing support via babeltrace.
 *
 * Copyright (C) 2014, Jiri Olsa <jolsa@redhat.com>
 * Copyright (C) 2014, Sebastian Andrzej Siewior <bigeasy@linutronix.de>
 *
 * Released under the GPL v2. (and only v2, not any later version)
 */

#include <linux/compiler.h>
#include <babeltrace/ctf-writer/writer.h>
#include <babeltrace/ctf-writer/clock.h>
#include <babeltrace/ctf-writer/stream.h>
#include <babeltrace/ctf-writer/event.h>
#include <babeltrace/ctf-writer/event-types.h>
#include <babeltrace/ctf-writer/event-fields.h>
#include <babeltrace/ctf/events.h>
#include <traceevent/event-parse.h>
#include "asm/bug.h"
#include "data-convert-bt.h"
#include "session.h"
#include "util.h"
#include "debug.h"
#include "tool.h"
#include "evlist.h"
#include "evsel.h"
#include "machine.h"

#define pr_N(n, fmt, ...) \
	eprintf(n, debug_data_convert, fmt, ##__VA_ARGS__)

#define pr(fmt, ...)  pr_N(1, pr_fmt(fmt), ##__VA_ARGS__)
#define pr2(fmt, ...) pr_N(2, pr_fmt(fmt), ##__VA_ARGS__)

#define pr_time2(t, fmt, ...) pr_time_N(2, debug_data_convert, t, pr_fmt(fmt), ##__VA_ARGS__)

struct evsel_priv {
	struct bt_ctf_event_class *event_class;
};

struct ctf_writer {
	/* writer primitives */
	struct bt_ctf_writer		*writer;
	struct bt_ctf_stream		*stream;
	struct bt_ctf_stream_class	*stream_class;
	struct bt_ctf_clock		*clock;

	/* data types */
	union {
		struct {
			struct bt_ctf_field_type	*s64;
			struct bt_ctf_field_type	*u64;
			struct bt_ctf_field_type	*s32;
			struct bt_ctf_field_type	*u32;
			struct bt_ctf_field_type	*string;
			struct bt_ctf_field_type	*u64_hex;
		};
		struct bt_ctf_field_type *array[6];
	} data;
};

struct convert {
	struct perf_tool	tool;
	struct ctf_writer	writer;

	u64			events_size;
	u64			events_count;
};

static int value_set(struct bt_ctf_field_type *type,
		     struct bt_ctf_event *event,
		     const char *name, u64 val)
{
	struct bt_ctf_field *field;
	bool sign = bt_ctf_field_type_integer_get_signed(type);
	int ret;

	field = bt_ctf_field_create(type);
	if (!field) {
		pr_err("failed to create a field %s\n", name);
		return -1;
	}

	if (sign) {
		ret = bt_ctf_field_signed_integer_set_value(field, val);
		if (ret) {
			pr_err("failed to set field value %s\n", name);
			goto err;
		}
	} else {
		ret = bt_ctf_field_unsigned_integer_set_value(field, val);
		if (ret) {
			pr_err("failed to set field value %s\n", name);
			goto err;
		}
	}

	ret = bt_ctf_event_set_payload(event, name, field);
	if (ret) {
		pr_err("failed to set payload %s\n", name);
		goto err;
	}

	pr2("  SET [%s = %" PRIu64 "]\n", name, val);

err:
	bt_ctf_field_put(field);
	return ret;
}

#define __FUNC_VALUE_SET(_name, _val_type)				\
static __maybe_unused int value_set_##_name(struct ctf_writer *cw,	\
			     struct bt_ctf_event *event,		\
			     const char *name,				\
			     _val_type val)				\
{									\
	struct bt_ctf_field_type *type = cw->data._name;		\
	return value_set(type, event, name, (u64) val);			\
}

#define FUNC_VALUE_SET(_name) __FUNC_VALUE_SET(_name, _name)

FUNC_VALUE_SET(s32)
FUNC_VALUE_SET(u32)
FUNC_VALUE_SET(s64)
FUNC_VALUE_SET(u64)
__FUNC_VALUE_SET(u64_hex, u64)

static struct bt_ctf_field_type*
get_tracepoint_field_type(struct ctf_writer *cw, struct format_field *field)
{
	unsigned long flags = field->flags;

	if (flags & FIELD_IS_STRING)
		return cw->data.string;

	if (!(flags & FIELD_IS_SIGNED)) {
		/* unsigned long are mostly pointers */
		if (flags & FIELD_IS_LONG || flags & FIELD_IS_POINTER)
			return cw->data.u64_hex;
	}

	if (flags & FIELD_IS_SIGNED) {
		if (field->size == 8)
			return cw->data.s64;
		else
			return cw->data.s32;
	}

	if (field->size == 8)
		return cw->data.u64;
	else
		return cw->data.u32;
}

static int add_tracepoint_field_value(struct ctf_writer *cw,
				      struct bt_ctf_event_class *event_class,
				      struct bt_ctf_event *event,
				      struct perf_sample *sample,
				      struct format_field *fmtf)
{
	struct bt_ctf_field_type *type;
	struct bt_ctf_field *array_field;
	struct bt_ctf_field *field;
	const char *name = fmtf->name;
	void *data = sample->raw_data;
	unsigned long long value_int;
	unsigned long flags = fmtf->flags;
	unsigned int n_items;
	unsigned int i;
	unsigned int offset;
	unsigned int len;
	int ret;

	offset = fmtf->offset;
	len = fmtf->size;
	if (flags & FIELD_IS_STRING)
		flags &= ~FIELD_IS_ARRAY;

	if (flags & FIELD_IS_DYNAMIC) {
		unsigned long long tmp_val;

		tmp_val = pevent_read_number(fmtf->event->pevent,
				data + offset, len);
		offset = tmp_val;
		len = offset >> 16;
		offset &= 0xffff;
	}

	if (flags & FIELD_IS_ARRAY) {

		type = bt_ctf_event_class_get_field_by_name(
				event_class, name);
		array_field = bt_ctf_field_create(type);
		bt_ctf_field_type_put(type);
		if (!array_field) {
			pr_err("Failed to create array type %s\n", name);
			return -1;
		}

		len = fmtf->size / fmtf->arraylen;
		n_items = fmtf->arraylen;
	} else {
		n_items = 1;
		array_field = NULL;
	}

	type = get_tracepoint_field_type(cw, fmtf);

	for (i = 0; i < n_items; i++) {
		if (!(flags & FIELD_IS_STRING))
			value_int = pevent_read_number(
					fmtf->event->pevent,
					data + offset + i * len, len);

		if (flags & FIELD_IS_ARRAY)
			field = bt_ctf_field_array_get_field(array_field, i);
		else
			field = bt_ctf_field_create(type);

		if (!field) {
			pr_err("failed to create a field %s\n", name);
			return -1;
		}

		if (flags & FIELD_IS_STRING)
			ret = bt_ctf_field_string_set_value(field,
					data + offset + i * len);
		else if (!(flags & FIELD_IS_SIGNED))
			ret = bt_ctf_field_unsigned_integer_set_value(
					field, value_int);
		else
			ret = bt_ctf_field_signed_integer_set_value(
					field, value_int);
		if (ret) {
			pr_err("failed to set file value %s\n", name);
			goto err_put_field;
		}
		if (!(flags & FIELD_IS_ARRAY)) {
			ret = bt_ctf_event_set_payload(event, name, field);
			if (ret) {
				pr_err("failed to set payload %s\n", name);
				goto err_put_field;
			}
		}
		bt_ctf_field_put(field);
	}
	if (flags & FIELD_IS_ARRAY) {
		ret = bt_ctf_event_set_payload(event, name, array_field);
		if (ret) {
			pr_err("Failed add payload array %s\n", name);
			return -1;
		}
		bt_ctf_field_put(array_field);
	}
	return 0;

err_put_field:
	bt_ctf_field_put(field);
	return -1;
}

static int add_tracepoint_fields_values(struct ctf_writer *cw,
					struct bt_ctf_event_class *event_class,
					struct bt_ctf_event *event,
					struct format_field *fields,
					struct perf_sample *sample)
{
	struct format_field *field;
	int ret;

	for (field = fields; field; field = field->next) {
		ret = add_tracepoint_field_value(cw, event_class, event, sample,
				field);
		if (ret)
			return -1;
	}
	return 0;
}

static int add_tracepoint_values(struct ctf_writer *cw,
				 struct bt_ctf_event_class *event_class,
				 struct bt_ctf_event *event,
				 struct perf_evsel *evsel,
				 struct perf_sample *sample)
{
	struct format_field *common_fields = evsel->tp_format->format.common_fields;
	struct format_field *fields        = evsel->tp_format->format.fields;
	int ret;

	ret = add_tracepoint_fields_values(cw, event_class, event,
					   common_fields, sample);
	if (!ret)
		ret = add_tracepoint_fields_values(cw, event_class, event,
						   fields, sample);

	return ret;
}

static int add_generic_values(struct ctf_writer *cw,
			      struct bt_ctf_event *event,
			      struct perf_evsel *evsel,
			      struct perf_sample *sample)
{
	u64 type = evsel->attr.sample_type;
	int ret;

	/*
	 * missing:
	 *   PERF_SAMPLE_TIME         - not needed as we have it in
	 *                              ctf event header
	 *   PERF_SAMPLE_READ         - TODO
	 *   PERF_SAMPLE_CALLCHAIN    - TODO
	 *   PERF_SAMPLE_RAW          - tracepoint fields are handled separately
	 *   PERF_SAMPLE_BRANCH_STACK - TODO
	 *   PERF_SAMPLE_REGS_USER    - TODO
	 *   PERF_SAMPLE_STACK_USER   - TODO
	 */

	if (type & PERF_SAMPLE_IP) {
		ret = value_set_u64_hex(cw, event, "perf_ip", sample->ip);
		if (ret)
			return -1;
	}

	if (type & PERF_SAMPLE_TID) {
		ret = value_set_s32(cw, event, "perf_tid", sample->tid);
		if (ret)
			return -1;

		ret = value_set_s32(cw, event, "perf_pid", sample->pid);
		if (ret)
			return -1;
	}

	if ((type & PERF_SAMPLE_ID) ||
	    (type & PERF_SAMPLE_IDENTIFIER)) {
		ret = value_set_u64(cw, event, "perf_id", sample->id);
		if (ret)
			return -1;
	}

	if (type & PERF_SAMPLE_STREAM_ID) {
		ret = value_set_u64(cw, event, "perf_stream_id", sample->stream_id);
		if (ret)
			return -1;
	}

	if (type & PERF_SAMPLE_CPU) {
		ret = value_set_u32(cw, event, "perf_cpu", sample->cpu);
		if (ret)
			return -1;
	}

	if (type & PERF_SAMPLE_PERIOD) {
		ret = value_set_u64(cw, event, "perf_period", sample->period);
		if (ret)
			return -1;
	}

	if (type & PERF_SAMPLE_WEIGHT) {
		ret = value_set_u64(cw, event, "perf_weight", sample->weight);
		if (ret)
			return -1;
	}

	if (type & PERF_SAMPLE_DATA_SRC) {
		ret = value_set_u64(cw, event, "perf_data_src",
				sample->data_src);
		if (ret)
			return -1;
	}

	if (type & PERF_SAMPLE_TRANSACTION) {
		ret = value_set_u64(cw, event, "perf_transaction",
				sample->transaction);
		if (ret)
			return -1;
	}

	return 0;
}

static int process_sample_event(struct perf_tool *tool,
				union perf_event *_event __maybe_unused,
				struct perf_sample *sample,
				struct perf_evsel *evsel,
				struct machine *machine __maybe_unused)
{
	struct convert *c = container_of(tool, struct convert, tool);
	struct evsel_priv *priv = evsel->priv;
	struct ctf_writer *cw = &c->writer;
	struct bt_ctf_event_class *event_class;
	struct bt_ctf_event *event;
	int ret;

	if (WARN_ONCE(!priv, "Failed to setup all events.\n"))
		return 0;

	event_class = priv->event_class;

	/* update stats */
	c->events_count++;
	c->events_size += _event->header.size;

	pr_time2(sample->time, "sample %" PRIu64 "\n", c->events_count);

	event = bt_ctf_event_create(event_class);
	if (!event) {
		pr_err("Failed to create an CTF event\n");
		return -1;
	}

	bt_ctf_clock_set_time(cw->clock, sample->time);

	ret = add_generic_values(cw, event, evsel, sample);
	if (ret)
		return -1;

	if (evsel->attr.type == PERF_TYPE_TRACEPOINT) {
		ret = add_tracepoint_values(cw, event_class, event,
					    evsel, sample);
		if (ret)
			return -1;
	}

	bt_ctf_stream_append_event(cw->stream, event);
	bt_ctf_event_put(event);
	return 0;
}

static int add_tracepoint_fields_types(struct ctf_writer *cw,
				       struct format_field *fields,
				       struct bt_ctf_event_class *event_class)
{
	struct format_field *field;
	int ret;

	for (field = fields; field; field = field->next) {
		struct bt_ctf_field_type *type;
		unsigned long flags = field->flags;

		pr2("  field '%s'\n", field->name);

		type = get_tracepoint_field_type(cw, field);
		if (!type)
			return -1;

		/*
		 * A string is an array of chars. For this we use the string
		 * type and don't care that it is an array. What we don't
		 * support is an array of strings.
		 */
		if (flags & FIELD_IS_STRING)
			flags &= ~FIELD_IS_ARRAY;

		if (flags & FIELD_IS_ARRAY)
			type = bt_ctf_field_type_array_create(type, field->arraylen);

		ret = bt_ctf_event_class_add_field(event_class, type,
				field->name);

		if (flags & FIELD_IS_ARRAY)
			bt_ctf_field_type_put(type);

		if (ret) {
			pr_err("Failed to add field '%s\n", field->name);
			return -1;
		}
	}

	return 0;
}

static int add_tracepoint_types(struct ctf_writer *cw,
				struct perf_evsel *evsel,
				struct bt_ctf_event_class *class)
{
	struct format_field *common_fields = evsel->tp_format->format.common_fields;
	struct format_field *fields        = evsel->tp_format->format.fields;
	int ret;

	ret = add_tracepoint_fields_types(cw, common_fields, class);
	if (!ret)
		ret = add_tracepoint_fields_types(cw, fields, class);

	return ret;
}

static int add_generic_types(struct ctf_writer *cw, struct perf_evsel *evsel,
			     struct bt_ctf_event_class *event_class)
{
	u64 type = evsel->attr.sample_type;

	/*
	 * missing:
	 *   PERF_SAMPLE_TIME         - not needed as we have it in
	 *                              ctf event header
	 *   PERF_SAMPLE_READ         - TODO
	 *   PERF_SAMPLE_CALLCHAIN    - TODO
	 *   PERF_SAMPLE_RAW          - tracepoint fields are handled separately
	 *   PERF_SAMPLE_BRANCH_STACK - TODO
	 *   PERF_SAMPLE_REGS_USER    - TODO
	 *   PERF_SAMPLE_STACK_USER   - TODO
	 */

#define ADD_FIELD(cl, t, n)						\
	do {								\
		pr2("  field '%s'\n", n);				\
		if (bt_ctf_event_class_add_field(cl, t, n)) {		\
			pr_err("Failed to add field '%s;\n", n);	\
			return -1;					\
		}							\
	} while (0)

	if (type & PERF_SAMPLE_IP)
		ADD_FIELD(event_class, cw->data.u64_hex, "perf_ip");

	if (type & PERF_SAMPLE_TID) {
		ADD_FIELD(event_class, cw->data.s32, "perf_tid");
		ADD_FIELD(event_class, cw->data.s32, "perf_pid");
	}

	if ((type & PERF_SAMPLE_ID) ||
	    (type & PERF_SAMPLE_IDENTIFIER))
		ADD_FIELD(event_class, cw->data.u64, "perf_id");

	if (type & PERF_SAMPLE_STREAM_ID)
		ADD_FIELD(event_class, cw->data.u64, "perf_stream_id");

	if (type & PERF_SAMPLE_CPU)
		ADD_FIELD(event_class, cw->data.u32, "perf_cpu");

	if (type & PERF_SAMPLE_PERIOD)
		ADD_FIELD(event_class, cw->data.u64, "perf_period");

	if (type & PERF_SAMPLE_WEIGHT)
		ADD_FIELD(event_class, cw->data.u64, "perf_weight");

	if (type & PERF_SAMPLE_DATA_SRC)
		ADD_FIELD(event_class, cw->data.u64, "perf_data_src");

	if (type & PERF_SAMPLE_TRANSACTION)
		ADD_FIELD(event_class, cw->data.u64, "perf_transaction");

#undef ADD_FIELD
	return 0;
}

static int add_event(struct ctf_writer *cw, struct perf_evsel *evsel)
{
	struct bt_ctf_event_class *event_class;
	struct evsel_priv *priv;
	const char *name = perf_evsel__name(evsel);
	int ret;

	pr("Adding event '%s' (type %d)\n", name, evsel->attr.type);

	event_class = bt_ctf_event_class_create(name);
	if (!event_class)
		return -1;

	ret = add_generic_types(cw, evsel, event_class);
	if (ret)
		goto err;

	if (evsel->attr.type == PERF_TYPE_TRACEPOINT) {
		ret = add_tracepoint_types(cw, evsel, event_class);
		if (ret)
			goto err;
	}

	ret = bt_ctf_stream_class_add_event_class(cw->stream_class, event_class);
	if (ret) {
		pr("Failed to add event class into stream.\n");
		goto err;
	}

	priv = malloc(sizeof(*priv));
	if (!priv)
		goto err;

	priv->event_class = event_class;
	evsel->priv       = priv;
	return 0;

err:
	bt_ctf_event_class_put(event_class);
	pr_err("Failed to add event '%s'.\n", name);
	return -1;
}

static int setup_events(struct ctf_writer *cw, struct perf_session *session)
{
	struct perf_evlist *evlist = session->evlist;
	struct perf_evsel *evsel;
	int ret;

	evlist__for_each(evlist, evsel) {
		ret = add_event(cw, evsel);
		if (ret)
			return ret;
	}
	return 0;
}

static int ctf_writer__setup_env(struct ctf_writer *cw,
				 struct perf_session *session)
{
	struct perf_header *header = &session->header;
	struct bt_ctf_writer *writer = cw->writer;

#define ADD(__n, __v)							\
do {									\
	if (bt_ctf_writer_add_environment_field(writer, __n, __v))	\
		return -1;						\
} while (0)

	ADD("host",    header->env.hostname);
	ADD("sysname", "Linux");
	ADD("release", header->env.os_release);
	ADD("version", header->env.version);
	ADD("machine", header->env.arch);
	ADD("domain", "kernel");
	ADD("tracer_name", "perf");

#undef ADD
	return 0;
}

static int ctf_writer__setup_clock(struct ctf_writer *cw)
{
	struct bt_ctf_clock *clock = cw->clock;

	bt_ctf_clock_set_description(clock, "perf clock");

#define SET(__n, __v)				\
do {						\
	if (bt_ctf_clock_set_##__n(clock, __v))	\
		return -1;			\
} while (0)

	SET(frequency,   1000000000);
	SET(offset_s,    0);
	SET(offset,      0);
	SET(precision,   10);
	SET(is_absolute, 0);

#undef SET
	return 0;
}

static struct bt_ctf_field_type *create_int_type(int size, bool sign, bool hex)
{
	struct bt_ctf_field_type *type;

	type = bt_ctf_field_type_integer_create(size);
	if (!type)
		return NULL;

	if (sign &&
	    bt_ctf_field_type_integer_set_signed(type, 1))
		goto err;

	if (hex &&
	    bt_ctf_field_type_integer_set_base(type, BT_CTF_INTEGER_BASE_HEXADECIMAL))
		goto err;

	pr2("Created type: INTEGER %d-bit %ssigned %s\n",
	    size, sign ? "un" : "", hex ? "hex" : "");
	return type;

err:
	bt_ctf_field_type_put(type);
	return NULL;
}

static void ctf_writer__cleanup_data(struct ctf_writer *cw)
{
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(cw->data.array); i++)
		bt_ctf_field_type_put(cw->data.array[i]);
}

static int ctf_writer__init_data(struct ctf_writer *cw)
{
#define CREATE_INT_TYPE(type, size, sign, hex)		\
do {							\
	(type) = create_int_type(size, sign, hex);	\
	if (!(type))					\
		goto err;				\
} while (0)

	CREATE_INT_TYPE(cw->data.s64, 64, true,  false);
	CREATE_INT_TYPE(cw->data.u64, 64, false, false);
	CREATE_INT_TYPE(cw->data.s32, 32, true,  false);
	CREATE_INT_TYPE(cw->data.u32, 32, false, false);
	CREATE_INT_TYPE(cw->data.u64_hex, 64, false, true);

	cw->data.string  = bt_ctf_field_type_string_create();
	if (cw->data.string)
		return 0;

err:
	ctf_writer__cleanup_data(cw);
	pr_err("Failed to create data types.\n");
	return -1;
}

static void ctf_writer__cleanup(struct ctf_writer *cw)
{
	ctf_writer__cleanup_data(cw);

	bt_ctf_clock_put(cw->clock);
	bt_ctf_stream_put(cw->stream);
	bt_ctf_stream_class_put(cw->stream_class);
	bt_ctf_writer_put(cw->writer);

	/* and NULL all the pointers */
	memset(cw, 0, sizeof(*cw));
}

static int ctf_writer__init(struct ctf_writer *cw, const char *path)
{
	struct bt_ctf_writer		*writer;
	struct bt_ctf_stream_class	*stream_class;
	struct bt_ctf_stream		*stream;
	struct bt_ctf_clock		*clock;

	/* CTF writer */
	writer = bt_ctf_writer_create(path);
	if (!writer)
		goto err;

	cw->writer = writer;

	/* CTF clock */
	clock = bt_ctf_clock_create("perf_clock");
	if (!clock) {
		pr("Failed to create CTF clock.\n");
		goto err_cleanup;
	}

	cw->clock = clock;

	if (ctf_writer__setup_clock(cw)) {
		pr("Failed to setup CTF clock.\n");
		goto err_cleanup;
	}

	/* CTF stream class */
	stream_class = bt_ctf_stream_class_create("perf_stream");
	if (!stream_class) {
		pr("Failed to create CTF stream class.\n");
		goto err_cleanup;
	}

	cw->stream_class = stream_class;

	/* CTF clock stream setup */
	if (bt_ctf_stream_class_set_clock(stream_class, clock)) {
		pr("Failed to assign CTF clock to stream class.\n");
		goto err_cleanup;
	}

	if (ctf_writer__init_data(cw))
		goto err_cleanup;

	/* CTF stream instance */
	stream = bt_ctf_writer_create_stream(writer, stream_class);
	if (!stream) {
		pr("Failed to create CTF stream.\n");
		goto err_cleanup;
	}

	cw->stream = stream;

	/* CTF clock writer setup */
	if (bt_ctf_writer_add_clock(writer, clock)) {
		pr("Failed to assign CTF clock to writer.\n");
		goto err_cleanup;
	}

	return 0;

err_cleanup:
	ctf_writer__cleanup(cw);
err:
	pr_err("Failed to setup CTF writer.\n");
	return -1;
}

int bt_convert__perf2ctf(const char *input, const char *path)
{
	struct perf_session *session;
	struct perf_data_file file = {
		.path = input,
		.mode = PERF_DATA_MODE_READ,
	};
	struct convert c = {
		.tool = {
			.sample          = process_sample_event,
			.mmap            = perf_event__process_mmap,
			.mmap2           = perf_event__process_mmap2,
			.comm            = perf_event__process_comm,
			.exit            = perf_event__process_exit,
			.fork            = perf_event__process_fork,
			.lost            = perf_event__process_lost,
			.tracing_data    = perf_event__process_tracing_data,
			.build_id        = perf_event__process_build_id,
			.ordered_events  = true,
			.ordering_requires_timestamps = true,
		},
	};
	struct ctf_writer *cw = &c.writer;
	int err = -1;

	/* CTF writer */
	if (ctf_writer__init(cw, path))
		return -1;

	/* perf.data session */
	session = perf_session__new(&file, 0, &c.tool);
	if (!session)
		goto free_writer;

	/* CTF writer env/clock setup  */
	if (ctf_writer__setup_env(cw, session))
		goto free_session;

	/* CTF events setup */
	if (setup_events(cw, session))
		goto free_session;

	err = perf_session__process_events(session);
	if (!err)
		err = bt_ctf_stream_flush(cw->stream);

	fprintf(stderr,
		"[ perf data convert: Converted '%s' into CTF data '%s' ]\n",
		file.path, path);

	fprintf(stderr,
		"[ perf data convert: Converted and wrote %.3f MB (%" PRIu64 " samples) ]\n",
		(double) c.events_size / 1024.0 / 1024.0,
		c.events_count);

	/* its all good */
free_session:
	perf_session__delete(session);

free_writer:
	ctf_writer__cleanup(cw);
	return err;
}