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Subject[PATCH 1/2] perf tools: Compare dso's also when comparing symbols
Date
From: Namhyung Kim <namhyung.kim@lge.com>

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>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
tools/perf/util/sort.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index 32c56377e008..1f9821db9e77 100644
--- 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);
}

--
1.7.11.7


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