[lttng-dev] [BABELTRACE PATCH] Parse LTTng indexes

Mathieu Desnoyers mathieu.desnoyers at efficios.com
Fri Nov 22 08:21:05 EST 2013


----- Original Message -----
> From: "Julien Desfossez" <jdesfossez at efficios.com>
> To: "mathieu desnoyers" <mathieu.desnoyers at efficios.com>
> Cc: lttng-dev at lists.lttng.org, "Julien Desfossez" <jdesfossez at efficios.com>
> Sent: Thursday, November 21, 2013 11:05:20 AM
> Subject: [BABELTRACE PATCH] Parse LTTng indexes
> 
> If a trace file has an associated index (same filename and .idx suffix in the
> "index" folder), we open it and use it instead of generating the index at
> open.

Please cut changelog at 72 or 76 lines. This is slightly too large for
git show.

> 
> Signed-off-by: Julien Desfossez <jdesfossez at efficios.com>
> ---
>  formats/ctf/ctf.c                  | 216
>  ++++++++++++++++++++++++++++++++++++-
>  include/Makefile.am                |   1 +
>  include/babeltrace/ctf/ctf-index.h |  58 ++++++++++
>  include/babeltrace/ctf/types.h     |   1 +
>  4 files changed, 271 insertions(+), 5 deletions(-)
>  create mode 100644 include/babeltrace/ctf/ctf-index.h
> 
> diff --git a/formats/ctf/ctf.c b/formats/ctf/ctf.c
> index 60d9c9f..7a0a383 100644
> --- a/formats/ctf/ctf.c
> +++ b/formats/ctf/ctf.c
> @@ -35,6 +35,7 @@
>  #include <babeltrace/context-internal.h>
>  #include <babeltrace/compat/uuid.h>
>  #include <babeltrace/endian.h>
> +#include <babeltrace/ctf/ctf-index.h>
>  #include <inttypes.h>
>  #include <stdio.h>
>  #include <sys/mman.h>
> @@ -71,6 +72,8 @@
>  
>  #define NSEC_PER_SEC 1000000000ULL
>  
> +#define INDEX_PATH "./index/%s.idx"
> +
>  int opt_clock_cycles,
>  	opt_clock_seconds,
>  	opt_clock_date,
> @@ -1666,6 +1669,153 @@ error:
>  	return ret;
>  }
>  
> +static
> +int import_stream_packet_index(struct ctf_trace *td,
> +		struct ctf_file_stream *file_stream)
> +{
> +	struct ctf_stream_declaration *stream;
> +	struct ctf_stream_pos *pos;
> +	struct ctf_packet_index ctf_index;
> +	struct ctf_packet_index_file_hdr index_hdr;
> +	uint64_t packet_map_len = DEFAULT_HEADER_LEN;
> +	struct packet_index index;
> +	int index_read;
> +	int ret = 0;
> +	int first_packet = 1;
> +	size_t filesize;
> +	struct stat filestats;
> +	size_t len;
> +
> +	pos = &file_stream->pos;
> +
> +	len = fread(&index_hdr, sizeof(index_hdr), 1, pos->index_fp);
> +	if (len != 1) {
> +		perror("read index file header");
> +		goto error;
> +	}
> +
> +	/* Check the index header */
> +	if (be32toh(index_hdr.magic) != CTF_INDEX_MAGIC) {
> +		fprintf(stderr, "[error] wrong index magic\n");
> +		ret = -1;
> +		goto error;
> +	}
> +	if (be32toh(index_hdr.index_major) != CTF_INDEX_MAJOR ||
> +			be32toh(index_hdr.index_minor) != CTF_INDEX_MINOR) {
> +		fprintf(stderr, "[error] Incompatible index file %" PRIu64
> +				".%" PRIu64 ", supported %d.%d\n",
> +				be64toh(index_hdr.index_major),
> +				be64toh(index_hdr.index_minor), CTF_INDEX_MAJOR,
> +				CTF_INDEX_MINOR);
> +		ret = -1;
> +		goto error;
> +	}
> +
> +	while((index_read = fread(&ctf_index, sizeof(ctf_index), 1, pos->index_fp))
> == 1) {

missing space after "while", should be cut into 2 lines.

> +		uint64_t stream_id;
> +		int len_index;
> +
> +		index.offset = be64toh(ctf_index.offset);
> +		index.packet_size = be64toh(ctf_index.packet_size);
> +		index.content_size = be64toh(ctf_index.content_size);
> +		index.timestamp_begin = be64toh(ctf_index.timestamp_begin);
> +		index.timestamp_end = be64toh(ctf_index.timestamp_end);
> +		index.events_discarded = be64toh(ctf_index.events_discarded);
> +		stream_id = be64toh(ctf_index.stream_id);
> +
> +		if (!first_packet) {
> +			/* add index to packet array */
> +			g_array_append_val(file_stream->pos.packet_cycles_index, index);
> +			continue;
> +		}
> +
> +		file_stream->parent.stream_id = stream_id;
> +		stream = g_ptr_array_index(td->streams, stream_id);
> +		if (!stream) {
> +			fprintf(stderr, "[error] Stream %" PRIu64
> +					" is not declared in metadata.\n",
> +					stream_id);
> +			ret = -EINVAL;
> +			goto error;
> +		}
> +		file_stream->parent.stream_class = stream;
> +		ret = create_stream_definitions(td, &file_stream->parent);
> +		if (ret)
> +			goto error;
> +
> +		ret = fstat(pos->fd, &filestats);
> +		if (ret < 0)
> +			goto error;
> +
> +		if (!filestats.st_size) {
> +			fprintf(stderr, "[error] Empty trace file\n");
> +			ret = -1;
> +			goto error;
> +		}
> +		filesize = filestats.st_size;
> +
> +		if (filesize - pos->mmap_offset < (packet_map_len >> LOG2_CHAR_BIT)) {
> +			packet_map_len = (filesize - pos->mmap_offset) << LOG2_CHAR_BIT;
> +		}
> +
> +		if (pos->base_mma) {
> +			/* unmap old base */
> +			ret = munmap_align(pos->base_mma);
> +			if (ret) {
> +				fprintf(stderr, "[error] Unable to unmap old base: %s.\n",
> +						strerror(errno));
> +				return ret;
> +			}
> +			pos->base_mma = NULL;
> +		}
> +		/* map new base. Need mapping length from header. */
> +		pos->base_mma = mmap_align(packet_map_len >> LOG2_CHAR_BIT, PROT_READ,
> +				MAP_PRIVATE, pos->fd, pos->mmap_offset);
> +		assert(pos->base_mma != MAP_FAILED);

It makes no sense to map the trace packets when we should just be pulling the index
from the index file. It makes the performance gain of having the index useless.

> +		/*
> +		 * Use current mapping size as temporary content and packet
> +		 * size.
> +		 */
> +		pos->content_size = packet_map_len;
> +		pos->packet_size = packet_map_len;
> +		pos->offset = 0;	/* Position of the packet header */
> +
> +		/* update trace_packet_header and stream_packet_context */
> +		if (pos->prot != PROT_WRITE && file_stream->parent.trace_packet_header) {
> +			/* Read packet header */
> +			ret = generic_rw(&pos->parent,
> &file_stream->parent.trace_packet_header->p);
> +			assert(!ret);
> +		}
> +		if (pos->prot != PROT_WRITE && file_stream->parent.stream_packet_context)
> {
> +			/* Read packet context */
> +			ret = generic_rw(&pos->parent,
> &file_stream->parent.stream_packet_context->p);
> +			assert(!ret);
> +		}
> +		index.data_offset = pos->offset;
> +
> +		/* read events discarded len from header */
> +		len_index = bt_struct_declaration_lookup_field_index(
> +				file_stream->parent.stream_packet_context->declaration,
> +				g_quark_from_static_string("events_discarded"));

The packet lost count in the index should already be extended to a 64-bit counter
by the consumer daemon. We should not need to get the len_index from the trace.

Is there any other reason why you map/unmap the trace ?

> +		if (len_index >= 0) {
> +			struct bt_definition *field;
> +
> +			field = bt_struct_definition_get_field_from_index(
> +					file_stream->parent.stream_packet_context,
> +					len_index);
> +			index.events_discarded_len = bt_get_int_len(field);
> +		}
> +		first_packet = 0;
> +		/* add index to packet array */
> +		g_array_append_val(file_stream->pos.packet_cycles_index, index);
> +	}
> +
> +	ret = 0;
> +
> +error:
> +	return ret;
> +}
> +
>  /*
>   * Note: many file streams can inherit from the same stream class
>   * description (metadata).
> @@ -1678,6 +1828,7 @@ int ctf_open_file_stream_read(struct ctf_trace *td,
> const char *path, int flags,
>  	int ret, fd, closeret;
>  	struct ctf_file_stream *file_stream;
>  	struct stat statbuf;
> +	char *index_name;
>  
>  	fd = openat(td->dirfd, path, flags);
>  	if (fd < 0) {
> @@ -1693,13 +1844,18 @@ int ctf_open_file_stream_read(struct ctf_trace *td,
> const char *path, int flags,
>  		goto fstat_error;
>  	}
>  	if (S_ISDIR(statbuf.st_mode)) {
> -		fprintf(stderr, "[warning] Skipping directory '%s' found in trace\n",
> path);
> +		if (strncmp(path, "index", 5) != 0) {
> +			fprintf(stderr, "[warning] Skipping directory '%s' "
> +					"found in trace\n", path);
> +		}
>  		ret = 0;
>  		goto fd_is_dir_ok;
>  	}
>  
>  	file_stream = g_new0(struct ctf_file_stream, 1);
>  	file_stream->pos.last_offset = LAST_OFFSET_POISON;
> +	file_stream->pos.fd = -1;
> +	file_stream->pos.index_fp = NULL;
>  
>  	strncpy(file_stream->parent.path, path, PATH_MAX);
>  	file_stream->parent.path[PATH_MAX - 1] = '\0';
> @@ -1722,19 +1878,61 @@ int ctf_open_file_stream_read(struct ctf_trace *td,
> const char *path, int flags,
>  	 * For now, only a single clock per trace is supported.
>  	 */
>  	file_stream->parent.current_clock = td->parent.single_clock;
> -	ret = create_stream_packet_index(td, file_stream);
> -	if (ret) {
> -		fprintf(stderr, "[error] Stream index creation error.\n");
> -		goto error_index;
> +
> +	/*
> +	 * Allocate the index name for this stream and try to open it.
> +	 */
> +	index_name = malloc((strlen(path) + sizeof(INDEX_PATH)) * sizeof(char));
> +	if (!index_name) {
> +		fprintf(stderr, "[error] Cannot allocate index filename\n");
> +		goto error_def;
> +	}
> +	snprintf(index_name, strlen(path) + sizeof(INDEX_PATH),
> +			INDEX_PATH, path);
> +
> +	if (faccessat(td->dirfd, index_name, O_RDONLY, flags) == 0) {

please exchange the ok and failure branches, and change the condition.
Everywhere else, the first branch is the " < 0" case (error).

> +		ret = openat(td->dirfd, index_name, flags);
> +		if (ret < 0) {
> +			perror("Index file openat()");
> +			ret = -1;
> +			goto error_free;
> +		}
> +		file_stream->pos.index_fp = fdopen(ret, "r");
> +		ret = import_stream_packet_index(td, file_stream);
> +		if (ret) {
> +			ret = -1;
> +			goto error_index;
> +		}
> +		ret = fclose(file_stream->pos.index_fp);
> +		if (ret < 0) {
> +			perror("close index");
> +			goto error_free;
> +		}
> +	} else {
> +		ret = create_stream_packet_index(td, file_stream);
> +		if (ret) {
> +			fprintf(stderr, "[error] Stream index creation error.\n");
> +			goto error_index;
> +		}
>  	}
> +	free(index_name);
> +
>  	/* Add stream file to stream class */
>  	g_ptr_array_add(file_stream->parent.stream_class->streams,
>  			&file_stream->parent);
>  	return 0;
>  
>  error_index:
> +	if (file_stream->pos.index_fp) {
> +		ret = fclose(file_stream->pos.index_fp);
> +		if (ret < 0) {
> +			perror("close index");
> +		}
> +	}
>  	if (file_stream->parent.trace_packet_header)
>  		bt_definition_unref(&file_stream->parent.trace_packet_header->p);
> +error_free:
> +	free(index_name);
>  error_def:
>  	closeret = ctf_fini_pos(&file_stream->pos);
>  	if (closeret) {
> @@ -1761,6 +1959,7 @@ int ctf_open_trace_read(struct ctf_trace *td,
>  	struct dirent *dirent;
>  	struct dirent *diriter;
>  	size_t dirent_len;
> +	char *ext;
>  
>  	td->flags = flags;
>  
> @@ -1816,6 +2015,13 @@ int ctf_open_trace_read(struct ctf_trace *td,
>  				|| !strcmp(diriter->d_name, "..")
>  				|| !strcmp(diriter->d_name, "metadata"))
>  			continue;
> +
> +		/* Ignore index files : *.idx */
> +		ext = strrchr(diriter->d_name, '.');
> +		if (ext && (!strcmp(ext, ".idx"))) {
> +			continue;
> +		}
> +
>  		ret = ctf_open_file_stream_read(td, diriter->d_name,
>  					flags, packet_seek);
>  		if (ret) {
> diff --git a/include/Makefile.am b/include/Makefile.am
> index ec927b9..d9996a7 100644
> --- a/include/Makefile.am
> +++ b/include/Makefile.am
> @@ -38,6 +38,7 @@ noinst_HEADERS = \
>  	babeltrace/ctf-text/types.h \
>  	babeltrace/ctf/types.h \
>  	babeltrace/ctf/callbacks-internal.h \
> +	babeltrace/ctf/ctf-index.h \
>  	babeltrace/ctf-writer/ref-internal.h \
>  	babeltrace/ctf-writer/writer-internal.h \
>  	babeltrace/ctf-writer/event-types-internal.h \
> diff --git a/include/babeltrace/ctf/ctf-index.h
> b/include/babeltrace/ctf/ctf-index.h
> new file mode 100644
> index 0000000..ee7ea26
> --- /dev/null
> +++ b/include/babeltrace/ctf/ctf-index.h
> @@ -0,0 +1,58 @@
> +/*
> + * Copyright (C) 2013 - Julien Desfossez <jdesfossez at efficios.com>
> + *                      Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> + *                      David Goulet <dgoulet at efficios.com>
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> copy
> + * of this software and associated documentation files (the "Software"), to
> deal
> + * in the Software without restriction, including without limitation the
> rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included
> in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
> OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> THE
> + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> THE
> + * SOFTWARE.
> + */
> +
> +#ifndef LTTNG_INDEX_H
> +#define LTTNG_INDEX_H
> +
> +#include <limits.h>
> +
> +#define CTF_INDEX_MAGIC 0xC11D81C1
> +#define CTF_INDEX_MAJOR 1
> +#define CTF_INDEX_MINOR 0
> +
> +/*
> + * Header at the beginning of each index file.
> + * All integer fields are stored in big endian.
> + */
> +struct ctf_packet_index_file_hdr {
> +	uint32_t magic;

You should submit the change to lttng-tools first.

Thanks,

Mathieu

> +	uint32_t index_major;
> +	uint32_t index_minor;
> +} __attribute__((__packed__));
> +
> +/*
> + * Packet index generated for each trace packet store in a trace file.
> + * All integer fields are stored in big endian.
> + */
> +struct ctf_packet_index {
> +	uint64_t offset;		/* offset of the packet in the file, in bytes */
> +	uint64_t packet_size;		/* packet size, in bits */
> +	uint64_t content_size;		/* content size, in bits */
> +	uint64_t timestamp_begin;
> +	uint64_t timestamp_end;
> +	uint64_t events_discarded;
> +	uint64_t stream_id;
> +} __attribute__((__packed__));
> +
> +#endif /* LTTNG_INDEX_H */
> diff --git a/include/babeltrace/ctf/types.h b/include/babeltrace/ctf/types.h
> index 96c5083..eeb0c57 100644
> --- a/include/babeltrace/ctf/types.h
> +++ b/include/babeltrace/ctf/types.h
> @@ -61,6 +61,7 @@ struct packet_index {
>  struct ctf_stream_pos {
>  	struct bt_stream_pos parent;
>  	int fd;			/* backing file fd. -1 if unset. */
> +	FILE *index_fp;		/* backing index file fp. NULL if unset. */
>  	GArray *packet_cycles_index;	/* contains struct packet_index in cycles */
>  	GArray *packet_real_index;	/* contains struct packet_index in ns */
>  	int prot;		/* mmap protection */
> --
> 1.8.3.2
> 
> 

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com



More information about the lttng-dev mailing list