3 files changed, 59 insertions, 0 deletions

diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 59cc0e12dd4..e12d539417b 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -28,6 +28,9 @@ bool ip_callchain__valid(struct ip_callchain *chain, const event_t *event)
 #define chain_for_each_child(child, parent)     \
         list_for_each_entry(child, &parent->children, brothers)
 
+#define chain_for_each_child_safe(child, next, parent)  \
+        list_for_each_entry_safe(child, next, &parent->children, brothers)
+
 static void
 rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
                     enum chain_mode mode)
@@ -406,3 +409,56 @@ end:
 
         return 0;
 }
+
+static int
+merge_chain_branch(struct callchain_node *dst, struct callchain_node *src,
+                   struct resolved_chain *chain)
+{
+        struct callchain_node *child, *next_child;
+        struct callchain_list *list, *next_list;
+        int old_pos = chain->nr;
+        int err = 0;
+
+        list_for_each_entry_safe(list, next_list, &src->val, list) {
+                chain->ips[chain->nr].ip = list->ip;
+                chain->ips[chain->nr].ms = list->ms;
+                chain->nr++;
+                list_del(&list->list);
+                free(list);
+        }
+
+        if (src->hit)
+                append_chain_children(dst, chain, 0, src->hit);
+
+        chain_for_each_child_safe(child, next_child, src) {
+                err = merge_chain_branch(dst, child, chain);
+                if (err)
+                        break;
+
+                list_del(&child->brothers);
+                free(child);
+        }
+
+        chain->nr = old_pos;
+
+        return err;
+}
+
+int callchain_merge(struct callchain_root *dst, struct callchain_root *src)
+{
+        struct resolved_chain *chain;
+        int err;
+
+        chain = malloc(sizeof(*chain) +
+                       src->max_depth * sizeof(struct resolved_ip));
+        if (!chain)
+                return -ENOMEM;
+
+        chain->nr = 0;
+
+        err = merge_chain_branch(&dst->node, &src->node, chain);
+
+        free(chain);
+
+        return err;
+}
diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
index 85b50fbeae5..51a8f2b600b 100644
--- a/tools/perf/util/callchain.h
+++ b/tools/perf/util/callchain.h
@@ -68,6 +68,7 @@ static inline u64 cumul_hits(struct callchain_node *node)
 int register_callchain_param(struct callchain_param *param);
 int callchain_append(struct callchain_root *root, struct ip_callchain *chain,
                      struct map_symbol *syms, u64 period);
+int callchain_merge(struct callchain_root *dst, struct callchain_root *src);
 
 bool ip_callchain__valid(struct ip_callchain *chain, const event_t *event);
 #endif  /* __PERF_CALLCHAIN_H */
diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index e77ff772463..2022e874099 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -226,6 +226,8 @@ static bool collapse__insert_entry(struct rb_root *root, struct hist_entry *he)
 
                 if (!cmp) {
                         iter->period += he->period;
+                        if (symbol_conf.use_callchain)
+                                callchain_merge(iter->callchain, he->callchain);
                         hist_entry__free(he);
                         return false;
                 }