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 <wangn...@huawei.com>
Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Cc: Jiri Olsa <jo...@kernel.org>
Cc: Masami Hiramatsu <mhira...@kernel.org>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Zefan Li <lize...@huawei.com>
Cc: Nilay Vaish <nilayva...@gmail.com>
Cc: He Kuang <heku...@huawei.com>
---
 tools/perf/tests/backward-ring-buffer.c | 103 ++++++++++++++++++++++++++------
 1 file changed, 84 insertions(+), 19 deletions(-)

diff --git a/tools/perf/tests/backward-ring-buffer.c 
b/tools/perf/tests/backward-ring-buffer.c
index 1750ef2..2e66c48 100644
--- a/tools/perf/tests/backward-ring-buffer.c
+++ b/tools/perf/tests/backward-ring-buffer.c
@@ -23,16 +23,34 @@ static void testcase(void)
        }
 }
 
+static void perf_evlist__mmap_read_catchup_all(struct perf_evlist *evlist)
+{
+       int i;
+
+       for (i = 0; i < evlist->nr_mmaps; i++)
+               perf_evlist__mmap_read_catchup(evlist, i);
+}
+
 static int count_samples(struct perf_evlist *evlist, int *sample_count,
                         int *comm_count)
 {
        int i;
+       union perf_event *(*reader)(struct perf_evlist *, int);
+
+       if (evlist->backward)
+               reader = perf_evlist__mmap_read_backward;
+       else
+               reader = perf_evlist__mmap_read_forward;
 
        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) {
+               /*
+                * Before calling count_samples(), ring buffers in backward
+                * evlist should have catched up with newest record
+                * using perf_evlist__mmap_read_catchup_all().
+                */
+               while ((event = (*reader)(evlist, i)) != NULL) {
                        const u32 type = event->header.type;
 
                        switch (type) {
@@ -51,34 +69,57 @@ 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)
+struct test_result {
+       int sys_enter;
+       int sys_exit;
+       int comm;
+};
+
+static int do_test(struct perf_evlist *evlist,
+                  struct perf_evlist *aux_evlist,
+                  int mmap_pages,
+                  struct test_result *res)
 {
        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);
+       perf_evlist__mmap_read_catchup_all(aux_evlist);
+       err = count_samples(aux_evlist, &res->sys_exit, &res->comm);
+       if (err)
+               goto errout;
+       err = count_samples(evlist, &res->sys_enter, &res->comm);
+       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;
        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 = {
@@ -90,6 +131,7 @@ int test__backward_ring_buffer(int subtest __maybe_unused)
                .mmap_pages   = 256,
                .default_interval = 1,
        };
+       struct test_result res = {0, 0, 0};
 
        snprintf(pid, sizeof(pid), "%d", getpid());
        pid[sizeof(pid) - 1] = '\0';
@@ -101,7 +143,6 @@ int test__backward_ring_buffer(int subtest __maybe_unused)
                return TEST_FAIL;
        }
 
-       evlist->backward = true;
        err = perf_evlist__create_maps(evlist, &opts.target);
        if (err < 0) {
                pr_debug("Not enough memory to create thread/cpu maps\n");
@@ -116,11 +157,21 @@ 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)->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 */
 
-       /* Set backward bit, ring buffer should be writing from end */
-       evlist__for_each_entry(evlist, evsel)
-               evsel->attr.write_backward = 1;
+       perf_evlist__config(evlist, &opts, NULL);
 
        err = perf_evlist__open(evlist);
        if (err < 0) {
@@ -129,24 +180,38 @@ 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,
-                     &comm_count);
+       err = do_test(evlist, aux_evlist, opts.mmap_pages, &res);
        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 (res.sys_enter != res.sys_exit) {
+               pr_err("Unexpected counter: sys_enter count=%d, sys_exit 
count=%d\n",
+                      res.sys_enter, res.sys_exit);
+               goto out_delete_evlist;
+       }
+
+       if ((res.sys_exit != NR_ITERS) || (res.comm != NR_ITERS)) {
+               pr_err("Unexpected counter: sys_exit count=%d, comm count=%d\n",
+                      res.sys_exit, res.comm);
                goto out_delete_evlist;
        }
 
-       err = do_test(evlist, 1, &sample_count, &comm_count);
+       err = do_test(evlist, aux_evlist, 1, &res);
        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

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