perf tools: Compare dso's also when comparing symbols

Linus reported that sometimes 'perf report -s symbol' exits without any
message on TUI.  David and Jiri found that it's because it failed to add
a hist entry due to an invalid symbol length.

It turns out that sorting by symbol (address) was broken since it only
compares symbol addresses.  The symbol address is a relative address
within a dso thus just checking its address can result in merging
unrelated symbols together.  Fix it by checking dso before comparing
symbol address.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1381802517-18812-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index 32c5637..1f9821d 100644 (file)
--- a/tools/perf/util/sort.c
+++ b/tools/perf/util/sort.c
@@ -182,9 +182,19 @@ static int64_t _sort__sym_cmp(struct symbol *sym_l, struct symbol *sym_r)
 static int64_t
 sort__sym_cmp(struct hist_entry *left, struct hist_entry *right)
 {
+       int64_t ret;
+
        if (!left->ms.sym && !right->ms.sym)
                return right->level - left->level;
 
+       /*
+        * comparing symbol address alone is not enough since it's a
+        * relative address within a dso.
+        */
+       ret = sort__dso_cmp(left, right);
+       if (ret != 0)
+               return ret;
+
        return _sort__sym_cmp(left->ms.sym, right->ms.sym);
 }