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Commit 05737464 authored by Wang Nan's avatar Wang Nan Committed by Arnaldo Carvalho de Melo
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perf record: Read from overwritable ring buffer 



Drive the evlist->bkw_mmap_state state machine during draining and when
SIGUSR2 is received. Read the backward ring buffer in record__mmap_read_all.

Signed-off-by: default avatarWang Nan <wangnan0@huawei.com>
Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1468485287-33422-12-git-send-email-wangnan0@huawei.com


Signed-off-by: default avatarHe Kuang <hekuang@huawei.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 54cc54de

tools/perf/builtin-record.c

+30 −1
Original line number Diff line number Diff line
@@ -555,7 +555,7 @@ static int record__mmap_read_all(struct record *rec) 
	if (err)

		return err;



	return err;

	return record__mmap_read_evlist(rec, rec->evlist, true);

}



static void record__init_features(struct record *rec)
@@ -953,6 +953,17 @@ static int __cmd_record(struct record *rec, int argc, const char **argv) 
	for (;;) {

		unsigned long long hits = rec->samples;



		/*

		 * rec->evlist->bkw_mmap_state is possible to be

		 * BKW_MMAP_EMPTY here: when done == true and

		 * hits != rec->samples in previous round.

		 *

		 * perf_evlist__toggle_bkw_mmap ensure we never

		 * convert BKW_MMAP_EMPTY to BKW_MMAP_DATA_PENDING.

		 */

		if (trigger_is_hit(&switch_output_trigger) || done || draining)

			perf_evlist__toggle_bkw_mmap(rec->evlist, BKW_MMAP_DATA_PENDING);



		if (record__mmap_read_all(rec) < 0) {

			trigger_error(&auxtrace_snapshot_trigger);

			trigger_error(&switch_output_trigger);
@@ -972,8 +983,26 @@ static int __cmd_record(struct record *rec, int argc, const char **argv) 
		}



		if (trigger_is_hit(&switch_output_trigger)) {

			/*

			 * If switch_output_trigger is hit, the data in

			 * overwritable ring buffer should have been collected,

			 * so bkw_mmap_state should be set to BKW_MMAP_EMPTY.

			 *

			 * If SIGUSR2 raise after or during record__mmap_read_all(),

			 * record__mmap_read_all() didn't collect data from

			 * overwritable ring buffer. Read again.

			 */

			if (rec->evlist->bkw_mmap_state == BKW_MMAP_RUNNING)

				continue;

			trigger_ready(&switch_output_trigger);



			/*

			 * Reenable events in overwrite ring buffer after

			 * record__mmap_read_all(): we should have collected

			 * data from it.

			 */

			perf_evlist__toggle_bkw_mmap(rec->evlist, BKW_MMAP_RUNNING);



			if (!quiet)

				fprintf(stderr, "[ perf record: dump data: Woken up %ld times ]\n",

					waking);