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Subject[PATCH v6 1/6] perf report: properly handle branch count in match_chain
Date
Some of the code paths I introduced before returned too early
without running the code to handle a node's branch count.
By refactoring match_chain to only have one exit point, this
can be remedied.

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Yao Jin <yao.jin@linux.intel.com>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
---
tools/perf/util/callchain.c | 129 +++++++++++++++++++++++---------------------
1 file changed, 67 insertions(+), 62 deletions(-)

diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 35a920f09503..ac767957fd9c 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -666,83 +666,88 @@ static enum match_result match_chain_strings(const char *left,
return ret;
}

+static enum match_result match_address_dso(struct dso *left_dso, u64 left_ip,
+ struct dso *right_dso, u64 right_ip)
+{
+ if (left_dso == right_dso && left_ip == right_ip)
+ return MATCH_EQ;
+ else if (left_ip < right_ip)
+ return MATCH_LT;
+ else
+ return MATCH_GT;
+}
+
static enum match_result match_chain(struct callchain_cursor_node *node,
struct callchain_list *cnode)
{
- 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_strings(cnode->srcline,
- node->srcline);
-
- /* if no srcline is available, fallback to symbol name */
- if (match == MATCH_ERROR && cnode->ms.sym && node->sym)
- match = match_chain_strings(cnode->ms.sym->name,
- node->sym->name);
+ enum match_result match = MATCH_ERROR;

+ switch (callchain_param.key) {
+ case CCKEY_SRCLINE:
+ match = match_chain_strings(cnode->srcline, node->srcline);
if (match != MATCH_ERROR)
- return match;
-
+ break;
+ /* otherwise fall-back to symbol-based comparison below */
+ __fallthrough;
+ case CCKEY_FUNCTION:
+ if (node->sym && cnode->ms.sym) {
+ /*
+ * Compare inlined frames based on their symbol name
+ * because different inlined frames will have the same
+ * symbol start. Otherwise do a faster comparison based
+ * on the symbol start address.
+ */
+ if (cnode->ms.sym->inlined || node->sym->inlined)
+ match = match_chain_strings(cnode->ms.sym->name,
+ node->sym->name);
+ else
+ match = match_address_dso(cnode->ms.map->dso,
+ cnode->ms.sym->start,
+ node->map->dso,
+ node->sym->start);
+ if (match != MATCH_ERROR)
+ break;
+ }
/* otherwise fall-back to IP-based comparison below */
+ __fallthrough;
+ case CCKEY_ADDRESS:
+ default:
+ match = match_address_dso(cnode->ms.map->dso, cnode->ip,
+ node->map->dso, node->ip);
+ break;
}

- if (cnode->ms.sym && sym && callchain_param.key == CCKEY_FUNCTION) {
- /*
- * Compare inlined frames based on their symbol name because
- * different inlined frames will have the same symbol start
- */
- if (cnode->ms.sym->inlined || node->sym->inlined)
- return match_chain_strings(cnode->ms.sym->name,
- node->sym->name);
-
- left = cnode->ms.sym->start;
- right = sym->start;
- left_dso = cnode->ms.map->dso;
- right_dso = node->map->dso;
- } else {
- left = cnode->ip;
- right = node->ip;
- }
-
- if (left == right && left_dso == right_dso) {
- if (node->branch) {
- cnode->branch_count++;
+ if (match == MATCH_EQ && node->branch) {
+ cnode->branch_count++;

- if (node->branch_from) {
- /*
- * It's "to" of a branch
- */
- cnode->brtype_stat.branch_to = true;
+ if (node->branch_from) {
+ /*
+ * It's "to" of a branch
+ */
+ cnode->brtype_stat.branch_to = true;

- if (node->branch_flags.predicted)
- cnode->predicted_count++;
+ if (node->branch_flags.predicted)
+ cnode->predicted_count++;

- if (node->branch_flags.abort)
- cnode->abort_count++;
+ if (node->branch_flags.abort)
+ cnode->abort_count++;

- branch_type_count(&cnode->brtype_stat,
- &node->branch_flags,
- node->branch_from,
- node->ip);
- } else {
- /*
- * It's "from" of a branch
- */
- cnode->brtype_stat.branch_to = false;
- cnode->cycles_count +=
- node->branch_flags.cycles;
- cnode->iter_count += node->nr_loop_iter;
- cnode->iter_cycles += node->iter_cycles;
- }
+ branch_type_count(&cnode->brtype_stat,
+ &node->branch_flags,
+ node->branch_from,
+ node->ip);
+ } else {
+ /*
+ * It's "from" of a branch
+ */
+ cnode->brtype_stat.branch_to = false;
+ cnode->cycles_count += node->branch_flags.cycles;
+ cnode->iter_count += node->nr_loop_iter;
+ cnode->iter_cycles += node->iter_cycles;
}
-
- return MATCH_EQ;
}

- return left > right ? MATCH_GT : MATCH_LT;
+ return match;
}

/*
--
2.14.2
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