[PATCH v7 2/8] perf tests: Add testcase for auxiliary evlist

[Wang Nan]

Improve test backward-ring-buffer, trace both enter and exit event of
prctl() syscall, utilize auxiliary evlist to mmap enter and exit event
into separated mmaps.

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: He Kuang <hekuang@xxxxxxxxxx>
---
 tools/perf/tests/backward-ring-buffer.c | 87 ++++++++++++++++++++++++++-------
 1 file changed, 68 insertions(+), 19 deletions(-)

diff --git a/tools/perf/tests/backward-ring-buffer.c b/tools/perf/tests/backward-ring-buffer.c
index d9ba991..76e34c0 100644
--- a/tools/perf/tests/backward-ring-buffer.c
+++ b/tools/perf/tests/backward-ring-buffer.c
@@ -31,16 +31,19 @@ static int count_samples(struct perf_evlist *evlist, int *sample_count,
 	for (i = 0; i < evlist->nr_mmaps; i++) {
 		union perf_event *event;
 
-		perf_evlist__mmap_read_catchup(evlist, i);
-		while ((event = perf_evlist__mmap_read_backward(evlist, i)) != NULL) {
+		if (evlist->backward)
+			perf_evlist__mmap_read_catchup(evlist, i);
+		while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) {
 			const u32 type = event->header.type;
 
 			switch (type) {
 			case PERF_RECORD_SAMPLE:
-				(*sample_count)++;
+				if (sample_count)
+					(*sample_count)++;
 				break;
 			case PERF_RECORD_COMM:
-				(*comm_count)++;
+				if (comm_count)
+					(*comm_count)++;
 				break;
 			default:
 				pr_err("Unexpected record of type %d\n", type);
@@ -51,34 +54,53 @@ static int count_samples(struct perf_evlist *evlist, int *sample_count,
 	return TEST_OK;
 }
 
-static int do_test(struct perf_evlist *evlist, int mmap_pages,
-		   int *sample_count, int *comm_count)
+static int do_test(struct perf_evlist *evlist,
+		   struct perf_evlist *aux_evlist,
+		   int mmap_pages,
+		   int *enter_sample_count,
+		   int *exit_sample_count,
+		   int *comm_count)
 {
 	int err;
 	char sbuf[STRERR_BUFSIZE];
 
-	err = perf_evlist__mmap(evlist, mmap_pages, true);
+	err = perf_evlist__mmap(evlist, mmap_pages, false);
 	if (err < 0) {
 		pr_debug("perf_evlist__mmap: %s\n",
 			 strerror_r(errno, sbuf, sizeof(sbuf)));
 		return TEST_FAIL;
 	}
 
+	err = perf_evlist__mmap(aux_evlist, mmap_pages, true);
+	if (err < 0) {
+		pr_debug("perf_evlist__mmap for aux_evlist: %s\n",
+			 strerror_r(errno, sbuf, sizeof(sbuf)));
+		return TEST_FAIL;
+	}
+
 	perf_evlist__enable(evlist);
 	testcase();
 	perf_evlist__disable(evlist);
 
-	err = count_samples(evlist, sample_count, comm_count);
+	err = count_samples(aux_evlist, exit_sample_count, comm_count);
+	if (err)
+		goto errout;
+	err = count_samples(evlist, enter_sample_count, NULL);
+	if (err)
+		goto errout;
+errout:
 	perf_evlist__munmap(evlist);
+	perf_evlist__munmap(aux_evlist);
 	return err;
 }
 
 
 int test__backward_ring_buffer(int subtest __maybe_unused)
 {
-	int ret = TEST_SKIP, err, sample_count = 0, comm_count = 0;
+	int ret = TEST_SKIP, err;
+	int enter_sample_count = 0, exit_sample_count = 0, comm_count = 0;
 	char pid[16], sbuf[STRERR_BUFSIZE];
-	struct perf_evlist *evlist;
+	struct perf_evlist *evlist, *aux_evlist = NULL;
 	struct perf_evsel *evsel __maybe_unused;
 	struct parse_events_error parse_error;
 	struct record_opts opts = {
@@ -115,11 +137,22 @@ int test__backward_ring_buffer(int subtest __maybe_unused)
 		goto out_delete_evlist;
 	}
 
-	perf_evlist__config(evlist, &opts, NULL);
+	/*
+	 * Set backward bit, ring buffer should be writing from end. Record
+	 * it in aux evlist
+	 */
+	perf_evlist__last(evlist)->overwrite = true;
+	perf_evlist__last(evlist)->attr.write_backward = 1;
 
-	/* Set backward bit, ring buffer should be writing from end */
-	evlist__for_each(evlist, evsel)
-		evsel->attr.write_backward = 1;
+	err = parse_events(evlist, "syscalls:sys_exit_prctl", &parse_error);
+	if (err) {
+		pr_debug("Failed to parse tracepoint event, try use root\n");
+		ret = TEST_SKIP;
+		goto out_delete_evlist;
+	}
+	/* Don't set backward bit for exit event. Record it in main evlist */
+
+	perf_evlist__config(evlist, &opts, NULL);
 
 	err = perf_evlist__open(evlist);
 	if (err < 0) {
@@ -128,24 +161,40 @@ int test__backward_ring_buffer(int subtest __maybe_unused)
 		goto out_delete_evlist;
 	}
 
+	aux_evlist = perf_evlist__new_aux(evlist);
+	if (!aux_evlist) {
+		pr_debug("perf_evlist__new_aux failed\n");
+		goto out_delete_evlist;
+	}
+	aux_evlist->backward = true;
+
 	ret = TEST_FAIL;
-	err = do_test(evlist, opts.mmap_pages, &sample_count,
+	err = do_test(evlist, aux_evlist, opts.mmap_pages,
+		      &enter_sample_count, &exit_sample_count,
 		      &comm_count);
 	if (err != TEST_OK)
 		goto out_delete_evlist;
 
-	if ((sample_count != NR_ITERS) || (comm_count != NR_ITERS)) {
-		pr_err("Unexpected counter: sample_count=%d, comm_count=%d\n",
-		       sample_count, comm_count);
+	if (enter_sample_count != exit_sample_count) {
+		pr_err("Unexpected counter: enter_sample_count=%d, exit_sample_count=%d\n",
+		       enter_sample_count, exit_sample_count);
+		goto out_delete_evlist;
+	}
+
+	if ((exit_sample_count != NR_ITERS) || (comm_count != NR_ITERS)) {
+		pr_err("Unexpected counter: exit_sample_count=%d, comm_count=%d\n",
+		       exit_sample_count, comm_count);
 		goto out_delete_evlist;
 	}
 
-	err = do_test(evlist, 1, &sample_count, &comm_count);
+	err = do_test(evlist, aux_evlist, 1, NULL, NULL, NULL);
 	if (err != TEST_OK)
 		goto out_delete_evlist;
 
 	ret = TEST_OK;
 out_delete_evlist:
+	if (aux_evlist)
+		perf_evlist__delete(aux_evlist);
 	perf_evlist__delete(evlist);
 	return ret;
 }
-- 
1.8.3.4