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-rw-r--r--tools/perf/Documentation/perf-record.txt8
-rw-r--r--tools/perf/builtin-record.c31
-rw-r--r--tools/perf/perf.h1
3 files changed, 34 insertions, 6 deletions
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;