[PATCH v4] perf annotate: Fix sample events lost in stdio mode

[Yang Jihong]

In hist__find_annotations function, since different hist_entry may point to same
symbol, we free notes->src to signal already processed this symbol in stdio 
mode;
when annotate, entry will skipped if notes->src is NULL to avoid repeated 
output.

However, there is a problem, for example, run the following command:

 # perf record -e branch-misses -e branch-instructions -a sleep 1

perf.data file contains different types of sample event.

If the same IP sample event exists in branch-misses and branch-instructions,
this event uses the same symbol. When annotate branch-misses events, notes->src
corresponding to this event is set to null, as a result, when annotate
branch-instructions events, this event is skipped and no annotate is output.

Solution of this patch is to remove zfree in hists__find_annotations and
change sort order to "dso,symbol" to avoid duplicate output when different
processes correspond to the same symbol.
---
 tools/perf/builtin-annotate.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/tools/perf/builtin-annotate.c b/tools/perf/builtin-annotate.c
index a23ba6bb99b6..ad169e3e2e8f 100644
--- a/tools/perf/builtin-annotate.c
+++ b/tools/perf/builtin-annotate.c
@@ -374,13 +374,6 @@ static void hists__find_annotations(struct hists *hists,
                } else {
                        hist_entry__tty_annotate(he, evsel, ann);
                        nd = rb_next(nd);
-                       /*
-                        * Since we have a hist_entry per IP for the same
-                        * symbol, free he->ms.sym->src to signal we already
-                        * processed this symbol.
-                        */
-                       zfree(&notes->src->cycles_hist);
-                       zfree(&notes->src);
                }
        }
 }
@@ -624,6 +617,12 @@ int cmd_annotate(int argc, const char **argv)
                if (setup_sorting(annotate.session->evlist) < 0)
                        usage_with_options(annotate_usage, options);
        } else {
+               /*
+                * Events of different processes may correspond to the same
+                * symbol, we do not care about the processes in annotate,
+                * set sort order to avoid repeated output.
+                */
+               sort_order = "dso,symbol";
                if (setup_sorting(NULL) < 0)
                        usage_with_options(annotate_usage, options);
        }
-- 
2.30.GIT