perf tools: Fix buildid processing

After recording, 'perf record' post-processes the data to determine which buildids are needed. That processing must process the data in time order, if possible, because otherwise dependent events, like forks and mmaps, will not make sense.

Signed-off-by Adrian Hunter <[email protected]>

---
  tools/perf/builtin-record.c | 11 +++++++++++
  1 file changed, 11 insertions(+)

tools/perf/builtin-record.c +0 -0

index de165a1b9240..f36b88938499 100644
@@ -500,6 +500,15 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
  		return -1;
  	}

tools/perf/builtin-record.c +2 -0

  	fd = perf_data_file__fd(file);
  	rec->session = session;
 

@@ -965,9 +974,11 @@ static struct record record = {
  	.tool = {
  		.sample		= process_sample_event,
  		.fork		= perf_event__process_fork,
+		.exit		= perf_event__process_exit,
  		.comm		= perf_event__process_comm,
  		.mmap		= perf_event__process_mmap,
  		.mmap2		= perf_event__process_mmap2,
+		.ordered_events	= true,
  	},
  };
 

Quoted 19 lines

After recording, 'perf record' post-processes the data to determine which buildids are needed. That processing must process the data in time order, if possible, because otherwise dependent events, like forks and mmaps, will not make sense.

Signed-off-by Adrian Hunter <[email protected]>

---
 tools/perf/builtin-record.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

tools/perf/builtin-record.c +0 -0

index de165a1b9240..f36b88938499 100644
@@ -500,6 +500,15 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 		return -1;
 	}
 

tools/perf/builtin-record.c static int __cmd_record(struct record *rec, int argc, const char **argv) · line 511

Quoted 9 lines

tools/perf/builtin-record.c +9 -0

+	/*
+	 * Normally perf_session__new would do this, but it doesn't have the
+	 * evlist.
+	 */
+	if (rec->tool.ordered_events && !perf_evlist__sample_id_all(rec->evlist)) {
+		dump_printf("WARNING: No sample_id_all support, falling back to unordered processing\n");
+		rec->tool.ordered_events = false;
+	}
+

In fact this chunk is misplaced, it needs to be below the call to record__open() after which the attributes are correctly configured. And dump_printf() is no good for 'perf record', pr_debug would be better. Don't have time to do that right now, I'll do it tommorow unless Arnaldo fixes it up.

Quoted 16 lines

tools/perf/builtin-record.c +2 -0

 	fd = perf_data_file__fd(file);
 	rec->session = session;
 

@@ -965,9 +974,11 @@ static struct record record = {
 	.tool = {
 		.sample		= process_sample_event,
 		.fork		= perf_event__process_fork,
+		.exit		= perf_event__process_exit,
 		.comm		= perf_event__process_comm,
 		.mmap		= perf_event__process_mmap,
 		.mmap2		= perf_event__process_mmap2,
+		.ordered_events	= true,
 	},
 };
 

Hi

Here are 3 patches related to the "getting stuck at end" problem.

The first patch dodges the deadlock.

The second patch stops fork from messing up i.e.
prevents the deadlock condition from arising in
the first place.

The third patch processes the data in order i.e.
prevents fork from having to deal with weird data
anyway.