Spdk/lib/trace_parser/trace.cpp

/*   SPDX-License-Identifier: BSD-3-Clause
 *   Copyright (C) 2021 Intel Corporation.
 *   All rights reserved.
 */

#include "spdk/stdinc.h"
#include "spdk/likely.h"
#include "spdk/log.h"
#include "spdk/trace_parser.h"
#include "spdk/util.h"

#include <exception>
#include <map>
#include <new>

struct entry_key {
	entry_key(uint16_t _lcore, uint64_t _tsc) : lcore(_lcore), tsc(_tsc) {}
	uint16_t lcore;
	uint64_t tsc;
};

class compare_entry_key
{
public:
	bool operator()(const entry_key &first, const entry_key &second) const
	{
		if (first.tsc == second.tsc) {
			return first.lcore < second.lcore;
		} else {
			return first.tsc < second.tsc;
		}
	}
};

typedef std::map<entry_key, spdk_trace_entry *, compare_entry_key> entry_map;

struct argument_context {
	spdk_trace_entry	*entry;
	spdk_trace_entry_buffer	*buffer;
	uint16_t		lcore;
	size_t			offset;

	argument_context(spdk_trace_entry *entry, uint16_t lcore) :
		entry(entry), lcore(lcore)
	{
		buffer = reinterpret_cast<spdk_trace_entry_buffer *>(entry);

		/* The first argument resides within the spdk_trace_entry structure, so the initial
		 * offset needs to be adjusted to the start of the spdk_trace_entry.args array
		 */
		offset = offsetof(spdk_trace_entry, args) -
			 offsetof(spdk_trace_entry_buffer, data);
	}
};

struct object_stats {
	std::map<uint64_t, uint64_t>	index;
	std::map<uint64_t, uint64_t>	start;
	uint64_t			counter;

	object_stats() : counter(0) {}
};

struct spdk_trace_parser {
	spdk_trace_parser(const spdk_trace_parser_opts *opts);
	~spdk_trace_parser();
	spdk_trace_parser(const spdk_trace_parser &) = delete;
	spdk_trace_parser &operator=(const spdk_trace_parser &) = delete;
	const spdk_trace_flags *flags() const { return &_histories->flags; }
	uint64_t tsc_offset() const { return _tsc_offset; }
	bool next_entry(spdk_trace_parser_entry *entry);
	uint64_t entry_count(uint16_t lcore) const;
private:
	spdk_trace_entry_buffer *get_next_buffer(spdk_trace_entry_buffer *buf, uint16_t lcore);
	bool build_arg(argument_context *argctx, const spdk_trace_argument *arg, int argid,
		       spdk_trace_parser_entry *pe);
	void populate_events(spdk_trace_history *history, int num_entries);
	bool init(const spdk_trace_parser_opts *opts);
	void cleanup();

	spdk_trace_histories	*_histories;
	size_t			_map_size;
	int			_fd;
	uint64_t		_tsc_offset;
	entry_map		_entries;
	entry_map::iterator	_iter;
	object_stats		_stats[SPDK_TRACE_MAX_OBJECT];
};

uint64_t
spdk_trace_parser::entry_count(uint16_t lcore) const
{
	spdk_trace_history *history;

	if (lcore >= SPDK_TRACE_MAX_LCORE) {
		return 0;
	}

	history = spdk_get_per_lcore_history(_histories, lcore);

	return history == NULL ? 0 : history->num_entries;
}

spdk_trace_entry_buffer *
spdk_trace_parser::get_next_buffer(spdk_trace_entry_buffer *buf, uint16_t lcore)
{
	spdk_trace_history *history;

	history = spdk_get_per_lcore_history(_histories, lcore);
	assert(history);

	if (spdk_unlikely(static_cast<void *>(buf) ==
			  static_cast<void *>(&history->entries[history->num_entries - 1]))) {
		return reinterpret_cast<spdk_trace_entry_buffer *>(&history->entries[0]);
	} else {
		return buf + 1;
	}
}

bool
spdk_trace_parser::build_arg(argument_context *argctx, const spdk_trace_argument *arg, int argid,
			     spdk_trace_parser_entry *pe)
{
	spdk_trace_entry *entry = argctx->entry;
	spdk_trace_entry_buffer *buffer = argctx->buffer;
	size_t curlen, argoff;

	argoff = 0;
	/* Make sure that if we only copy a 4-byte integer, that the upper bytes have already been
	 * zeroed.
	 */
	pe->args[argid].integer = 0;
	while (argoff < arg->size) {
		if (argctx->offset == sizeof(buffer->data)) {
			buffer = get_next_buffer(buffer, argctx->lcore);
			if (spdk_unlikely(buffer->tpoint_id != SPDK_TRACE_MAX_TPOINT_ID ||
					  buffer->tsc != entry->tsc)) {
				return false;
			}

			argctx->offset = 0;
			argctx->buffer = buffer;
		}

		curlen = spdk_min(sizeof(buffer->data) - argctx->offset, arg->size - argoff);
		if (argoff < sizeof(pe->args[0])) {
			memcpy(&pe->args[argid].string[argoff], &buffer->data[argctx->offset],
			       spdk_min(curlen, sizeof(pe->args[0]) - argoff));
		}

		argctx->offset += curlen;
		argoff += curlen;
	}

	return true;
}

bool
spdk_trace_parser::next_entry(spdk_trace_parser_entry *pe)
{
	spdk_trace_tpoint *tpoint;
	spdk_trace_entry *entry;
	object_stats *stats;
	std::map<uint64_t, uint64_t>::iterator related_kv;

	if (_iter == _entries.end()) {
		return false;
	}

	pe->entry = entry = _iter->second;
	pe->lcore = _iter->first.lcore;
	/* Set related index to the max value to indicate "empty" state */
	pe->related_index = UINT64_MAX;
	pe->related_type = OBJECT_NONE;
	tpoint = &_histories->flags.tpoint[entry->tpoint_id];
	stats = &_stats[tpoint->object_type];

	if (tpoint->new_object) {
		stats->index[entry->object_id] = stats->counter++;
		stats->start[entry->object_id] = entry->tsc;
	}

	if (tpoint->object_type != OBJECT_NONE) {
		if (spdk_likely(stats->start.find(entry->object_id) != stats->start.end())) {
			pe->object_index = stats->index[entry->object_id];
			pe->object_start = stats->start[entry->object_id];
		} else {
			pe->object_index = UINT64_MAX;
			pe->object_start = UINT64_MAX;
		}
	}

	argument_context argctx(entry, pe->lcore);
	for (uint8_t i = 0; i < tpoint->num_args; ++i) {
		if (!build_arg(&argctx, &tpoint->args[i], i, pe)) {
			SPDK_ERRLOG("Failed to parse tracepoint argument\n");
			return false;
		}
	}

	for (uint8_t i = 0; i < SPDK_TRACE_MAX_RELATIONS; ++i) {
		/* The relations are stored inside a tpoint, which means there might be
		 * multiple objects bound to a single tpoint. */
		if (tpoint->related_objects[i].object_type == OBJECT_NONE) {
			break;
		}
		stats = &_stats[tpoint->related_objects[i].object_type];
		related_kv = stats->index.find(reinterpret_cast<uint64_t>
					       (pe->args[tpoint->related_objects[i].arg_index].pointer));
		/* To avoid parsing the whole array, object index and type are stored
		 * directly inside spdk_trace_parser_entry. */
		if (related_kv != stats->index.end()) {
			pe->related_index = related_kv->second;
			pe->related_type = tpoint->related_objects[i].object_type;
			break;
		}
	}

	_iter++;
	return true;
}

void
spdk_trace_parser::populate_events(spdk_trace_history *history, int num_entries)
{
	int i, num_entries_filled;
	spdk_trace_entry *e;
	int first, last, lcore;

	lcore = history->lcore;
	e = history->entries;

	num_entries_filled = num_entries;
	while (e[num_entries_filled - 1].tsc == 0) {
		num_entries_filled--;
	}

	if (num_entries == num_entries_filled) {
		first = last = 0;
		for (i = 1; i < num_entries; i++) {
			if (e[i].tsc < e[first].tsc) {
				first = i;
			}
			if (e[i].tsc > e[last].tsc) {
				last = i;
			}
		}
	} else {
		first = 0;
		last = num_entries_filled - 1;
	}

	/*
	 * We keep track of the highest first TSC out of all reactors.
	 *  We will ignore any events that occurred before this TSC on any
	 *  other reactors.  This will ensure we only print data for the
	 *  subset of time where we have data across all reactors.
	 */
	if (e[first].tsc > _tsc_offset) {
		_tsc_offset = e[first].tsc;
	}

	i = first;
	while (1) {
		if (e[i].tpoint_id != SPDK_TRACE_MAX_TPOINT_ID) {
			_entries[entry_key(lcore, e[i].tsc)] = &e[i];
		}
		if (i == last) {
			break;
		}
		i++;
		if (i == num_entries_filled) {
			i = 0;
		}
	}
}

bool
spdk_trace_parser::init(const spdk_trace_parser_opts *opts)
{
	spdk_trace_history *history;
	struct stat st;
	int rc, i;

	switch (opts->mode) {
	case SPDK_TRACE_PARSER_MODE_FILE:
		_fd = open(opts->filename, O_RDONLY);
		break;
	case SPDK_TRACE_PARSER_MODE_SHM:
		_fd = shm_open(opts->filename, O_RDONLY, 0600);
		break;
	default:
		SPDK_ERRLOG("Invalid mode: %d\n", opts->mode);
		return false;
	}

	if (_fd < 0) {
		SPDK_ERRLOG("Could not open trace file: %s (%d)\n", opts->filename, errno);
		return false;
	}

	rc = fstat(_fd, &st);
	if (rc < 0) {
		SPDK_ERRLOG("Could not get size of trace file: %s\n", opts->filename);
		return false;
	}

	if ((size_t)st.st_size < sizeof(*_histories)) {
		SPDK_ERRLOG("Invalid trace file: %s\n", opts->filename);
		return false;
	}

	/* Map the header of trace file */
	_map_size = sizeof(*_histories);
	_histories = static_cast<spdk_trace_histories *>(mmap(NULL, _map_size, PROT_READ,
			MAP_SHARED, _fd, 0));
	if (_histories == MAP_FAILED) {
		SPDK_ERRLOG("Could not mmap trace file: %s\n", opts->filename);
		_histories = NULL;
		return false;
	}

	/* Remap the entire trace file */
	_map_size = spdk_get_trace_histories_size(_histories);
	munmap(_histories, sizeof(*_histories));
	if ((size_t)st.st_size < _map_size) {
		SPDK_ERRLOG("Trace file %s is not valid\n", opts->filename);
		_histories = NULL;
		return false;
	}
	_histories = static_cast<spdk_trace_histories *>(mmap(NULL, _map_size, PROT_READ,
			MAP_SHARED, _fd, 0));
	if (_histories == MAP_FAILED) {
		SPDK_ERRLOG("Could not mmap trace file: %s\n", opts->filename);
		_histories = NULL;
		return false;
	}

	if (opts->lcore == SPDK_TRACE_MAX_LCORE) {
		for (i = 0; i < SPDK_TRACE_MAX_LCORE; i++) {
			history = spdk_get_per_lcore_history(_histories, i);
			if (history == NULL || history->num_entries == 0 || history->entries[0].tsc == 0) {
				continue;
			}

			populate_events(history, history->num_entries);
		}
	} else {
		history = spdk_get_per_lcore_history(_histories, opts->lcore);
		if (history == NULL) {
			SPDK_ERRLOG("Trace file %s has no trace history for lcore %d\n",
				    opts->filename, opts->lcore);
			return false;
		}
		if (history->num_entries > 0 && history->entries[0].tsc != 0) {
			populate_events(history, history->num_entries);
		}
	}

	_iter = _entries.begin();
	return true;
}

void
spdk_trace_parser::cleanup()
{
	if (_histories != NULL) {
		munmap(_histories, _map_size);
	}

	if (_fd > 0) {
		close(_fd);
	}
}

spdk_trace_parser::spdk_trace_parser(const spdk_trace_parser_opts *opts) :
	_histories(NULL),
	_map_size(0),
	_fd(-1),
	_tsc_offset(0)
{
	if (!init(opts)) {
		cleanup();
		throw std::exception();
	}
}

spdk_trace_parser::~spdk_trace_parser()
{
	cleanup();
}

struct spdk_trace_parser *
spdk_trace_parser_init(const struct spdk_trace_parser_opts *opts)
{
	try {
		return new spdk_trace_parser(opts);
	} catch (...) {
		return NULL;
	}
}

void
spdk_trace_parser_cleanup(struct spdk_trace_parser *parser)
{
	delete parser;
}

const struct spdk_trace_flags *
spdk_trace_parser_get_flags(const struct spdk_trace_parser *parser)
{
	return parser->flags();
}

uint64_t
spdk_trace_parser_get_tsc_offset(const struct spdk_trace_parser *parser)
{
	return parser->tsc_offset();
}

bool
spdk_trace_parser_next_entry(struct spdk_trace_parser *parser,
			     struct spdk_trace_parser_entry *entry)
{
	return parser->next_entry(entry);
}

uint64_t
spdk_trace_parser_get_entry_count(const struct spdk_trace_parser *parser, uint16_t lcore)
{
	return parser->entry_count(lcore);
}