From 2328c2cd0bc0e04bdf7d26ad37792dfb09692151 Mon Sep 17 00:00:00 2001 From: Julien Desfossez Date: Wed, 19 Aug 2015 21:19:58 -0400 Subject: [PATCH] Output a warning if packets are lost MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Depends on the packet_seq_num fields available in the CTF index v1.1 (produced by LTTng 2.8). Same limitation as the events discarded information: if a stream is split in multiple files, the counters might not report the appropriate information for now. Signed-off-by: Julien Desfossez Signed-off-by: Jérémie Galarneau --- formats/ctf/ctf.c | 40 ++++++++++++++++++++++++---- include/babeltrace/ctf-ir/metadata.h | 2 ++ 2 files changed, 37 insertions(+), 5 deletions(-) diff --git a/formats/ctf/ctf.c b/formats/ctf/ctf.c index 917e9501..da9047e3 100644 --- a/formats/ctf/ctf.c +++ b/formats/ctf/ctf.c @@ -421,16 +421,26 @@ void print_uuid(FILE *fp, unsigned char *uuid) * Given we have discarded counters of those two types merged into the * events_discarded counter, we need to use the union of those ranges: * [ prev_timestamp_end, timestamp_end ] + * + * Lost packets occur if the tracer overwrote some subbuffer(s) before the + * consumer had time to extract them. We keep track of those gaps with the + * packet sequence number in each packet. */ static -void ctf_print_discarded(FILE *fp, struct ctf_stream_definition *stream) +void ctf_print_discarded_lost(FILE *fp, struct ctf_stream_definition *stream) { - if (!stream->events_discarded || !babeltrace_ctf_console_output) { + if ((!stream->events_discarded && !stream->packets_lost) || + !babeltrace_ctf_console_output) { return; } fflush(stdout); - fprintf(fp, "[warning] Tracer discarded %" PRIu64 " events between [", - stream->events_discarded); + if (stream->events_discarded) { + fprintf(fp, "[warning] Tracer discarded %" PRIu64 " events between [", + stream->events_discarded); + } else if (stream->packets_lost) { + fprintf(fp, "[warning] Tracer lost %" PRIu64 " trace packets between [", + stream->packets_lost); + } if (opt_clock_cycles) { ctf_print_timestamp(fp, stream, stream->prev.cycles.end); @@ -803,6 +813,7 @@ void ctf_update_current_packet_index(struct ctf_stream_definition *stream, struct packet_index *cur_index) { uint64_t events_discarded_diff; + uint64_t packets_lost_diff = 0; /* Update packet index time information */ @@ -830,6 +841,11 @@ void ctf_update_current_packet_index(struct ctf_stream_definition *stream, prev_index->ts_real.timestamp_end; events_discarded_diff -= prev_index->events_discarded; + /* packet_seq_num stays at 0 if not produced by the tracer */ + if (cur_index->packet_seq_num) { + packets_lost_diff = cur_index->packet_seq_num - + prev_index->packet_seq_num - 1; + } /* * Deal with 32-bit wrap-around if the tracer provided a * 32-bit field. @@ -850,6 +866,7 @@ void ctf_update_current_packet_index(struct ctf_stream_definition *stream, stream->current.real.begin; } stream->events_discarded = events_discarded_diff; + stream->packets_lost = packets_lost_diff; } /* @@ -960,7 +977,7 @@ void ctf_packet_seek(struct bt_stream_pos *stream_pos, size_t index, int whence) * timestamps. */ if ((&file_stream->parent)->stream_class->trace->parent.collection) { - ctf_print_discarded(stderr, &file_stream->parent); + ctf_print_discarded_lost(stderr, &file_stream->parent); } packet_index = &g_array_index(pos->packet_index, @@ -1690,6 +1707,19 @@ begin: packet_index.events_discarded = bt_get_unsigned_int(field); packet_index.events_discarded_len = bt_get_int_len(field); } + + /* read packet_seq_num from header */ + len_index = bt_struct_declaration_lookup_field_index( + file_stream->parent.stream_packet_context->declaration, + g_quark_from_static_string("packet_seq_num")); + if (len_index >= 0) { + struct bt_definition *field; + + field = bt_struct_definition_get_field_from_index( + file_stream->parent.stream_packet_context, + len_index); + packet_index.packet_seq_num = bt_get_unsigned_int(field); + } } else { /* Use file size for packet size */ packet_index.packet_size = filesize * CHAR_BIT; diff --git a/include/babeltrace/ctf-ir/metadata.h b/include/babeltrace/ctf-ir/metadata.h index 67536958..bc685801 100644 --- a/include/babeltrace/ctf-ir/metadata.h +++ b/include/babeltrace/ctf-ir/metadata.h @@ -74,6 +74,8 @@ struct ctf_stream_definition { /* Event discarded information */ uint64_t events_discarded; + /* Trace packets lost */ + uint64_t packets_lost; struct ctf_stream_packet_timestamp prev; struct ctf_stream_packet_timestamp current; char path[PATH_MAX]; /* Path to stream. '\0' for mmap traces */ -- 2.34.1