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Subject[RFC] perf callchain: Compare dsos (as well) for CCKEY_FUNCTION
Date
Two functions from different binaries can have same start
address. Thus, comparing only start address in match_chain()
leads to inconsistent callchains. Fix this by adding a check
for dsos as well.

Ex, https://www.spinics.net/lists/linux-perf-users/msg04067.html

Reported-by: Alexander Pozdneev <pozdneyev@gmail.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
---
tools/perf/util/callchain.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 510b513..6d5a483 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -678,6 +678,9 @@ static enum match_result match_chain(struct callchain_cursor_node *node,
{
struct symbol *sym = node->sym;
u64 left, right;
+ struct dso *left_dso = NULL;
+ struct dso *right_dso = NULL;
+

if (callchain_param.key == CCKEY_SRCLINE) {
enum match_result match = match_chain_srcline(node, cnode);
@@ -689,12 +692,16 @@ static enum match_result match_chain(struct callchain_cursor_node *node,
if (cnode->ms.sym && sym && callchain_param.key == CCKEY_FUNCTION) {
left = cnode->ms.sym->start;
right = sym->start;
+ if (cnode->ms.map && node->map) {
+ left_dso = cnode->ms.map->dso;
+ right_dso = node->map->dso;
+ }
} else {
left = cnode->ip;
right = node->ip;
}

- if (left == right) {
+ if (left == right && left_dso == right_dso) {
if (node->branch) {
cnode->branch_count++;

--
1.8.3.1
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