diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index 384c630436f8..69966abf65d1 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -367,6 +367,12 @@ options. 'perf record --dry-run -e' can act as a BPF script compiler if llvm.dump-obj in config file is set to true. +--tail-synthesize:: +Instead of collecting non-sample events (for example, fork, comm, mmap) at +the beginning of record, collect them during finalizing an output file. +The collected non-sample events reflects the status of the system when +record is finished. + --overwrite:: Makes all events use an overwritable ring buffer. An overwritable ring buffer works like a flight recorder: when it gets full, the kernel will @@ -381,6 +387,8 @@ those fitting in the ring buffer at that moment. 'overwrite' attribute can also be set or canceled for an event using config terms. For example: 'cycles/overwrite/' and 'instructions/no-overwrite/'. +Implies --tail-synthesize. + SEE ALSO -------- linkperf:perf-stat[1], linkperf:perf-list[1] diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 39c7486f0607..8f2c16d9275f 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -604,13 +604,16 @@ record__finish_output(struct record *rec) return; } -static int record__synthesize_workload(struct record *rec) +static int record__synthesize_workload(struct record *rec, bool tail) { struct { struct thread_map map; struct thread_map_data map_data; } thread_map; + if (rec->opts.tail_synthesize != tail) + return 0; + thread_map.map.nr = 1; thread_map.map.map[0].pid = rec->evlist->workload.pid; thread_map.map.map[0].comm = NULL; @@ -621,7 +624,7 @@ static int record__synthesize_workload(struct record *rec) rec->opts.proc_map_timeout); } -static int record__synthesize(struct record *rec); +static int record__synthesize(struct record *rec, bool tail); static int record__switch_output(struct record *rec, bool at_exit) @@ -632,6 +635,10 @@ record__switch_output(struct record *rec, bool at_exit) /* Same Size: "2015122520103046"*/ char timestamp[] = "InvalidTimestamp"; + record__synthesize(rec, true); + if (target__none(&rec->opts.target)) + record__synthesize_workload(rec, true); + rec->samples = 0; record__finish_output(rec); err = fetch_current_timestamp(timestamp, sizeof(timestamp)); @@ -654,7 +661,7 @@ record__switch_output(struct record *rec, bool at_exit) /* Output tracking events */ if (!at_exit) { - record__synthesize(rec); + record__synthesize(rec, false); /* * In 'perf record --switch-output' without -a, @@ -666,7 +673,7 @@ record__switch_output(struct record *rec, bool at_exit) * perf_event__synthesize_thread_map() for those events. */ if (target__none(&rec->opts.target)) - record__synthesize_workload(rec); + record__synthesize_workload(rec, false); } return fd; } @@ -720,7 +727,7 @@ static const struct perf_event_mmap_page *record__pick_pc(struct record *rec) return NULL; } -static int record__synthesize(struct record *rec) +static int record__synthesize(struct record *rec, bool tail) { struct perf_session *session = rec->session; struct machine *machine = &session->machines.host; @@ -730,6 +737,9 @@ static int record__synthesize(struct record *rec) int fd = perf_data_file__fd(file); int err = 0; + if (rec->opts.tail_synthesize != tail) + return 0; + if (file->is_pipe) { err = perf_event__synthesize_attrs(tool, session, process_synthesized_event); @@ -893,7 +903,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv) machine = &session->machines.host; - err = record__synthesize(rec); + err = record__synthesize(rec, false); if (err < 0) goto out_child; @@ -1057,6 +1067,9 @@ static int __cmd_record(struct record *rec, int argc, const char **argv) if (!quiet) fprintf(stderr, "[ perf record: Woken up %ld times to write data ]\n", waking); + if (target__none(&rec->opts.target)) + record__synthesize_workload(rec, true); + out_child: if (forks) { int exit_status; @@ -1075,6 +1088,7 @@ out_child: } else status = err; + record__synthesize(rec, true); /* this will be recalculated during process_buildids() */ rec->samples = 0; @@ -1399,6 +1413,8 @@ struct option __record_options[] = { OPT_BOOLEAN_SET('i', "no-inherit", &record.opts.no_inherit, &record.opts.no_inherit_set, "child tasks do not inherit counters"), + OPT_BOOLEAN(0, "tail-synthesize", &record.opts.tail_synthesize, + "synthesize non-sample events at the end of output"), OPT_BOOLEAN(0, "overwrite", &record.opts.overwrite, "use overwrite mode"), OPT_UINTEGER('F', "freq", &record.opts.user_freq, "profile at this frequency"), OPT_CALLBACK('m', "mmap-pages", &record.opts, "pages[,pages]", @@ -1610,6 +1626,9 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused) } } + if (record.opts.overwrite) + record.opts.tail_synthesize = true; + if (rec->evlist->nr_entries == 0 && perf_evlist__add_default(rec->evlist) < 0) { pr_err("Not enough memory for event selector list\n"); diff --git a/tools/perf/perf.h b/tools/perf/perf.h index 608b42bdb1b6..a7e0f1497244 100644 --- a/tools/perf/perf.h +++ b/tools/perf/perf.h @@ -59,6 +59,7 @@ struct record_opts { bool record_switch_events; bool all_kernel; bool all_user; + bool tail_synthesize; bool overwrite; unsigned int freq; unsigned int mmap_pages;