perf: Keep track of the max depth of a callchain

In order to implement callchains collapsing, we need to keep
track of the maximum depth in a histogram tree of callchains.
This way we'll avoid allocating an arbitrary temporary buffer
size on callchain merge time.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Christoph Hellwig <hch@infradead.org>

1 files changed, 13 insertions, 10 deletions

diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index f231f43424d2..f0b23f309edc 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -86,10 +86,10 @@ __sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
  * sort them by hit
  */
 static void
-sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
+sort_chain_flat(struct rb_root *rb_root, struct callchain_root *root,
                 u64 min_hit, struct callchain_param *param __used)
 {
-        __sort_chain_flat(rb_root, node, min_hit);
+        __sort_chain_flat(rb_root, &root->node, min_hit);
 }
 
 static void __sort_chain_graph_abs(struct callchain_node *node,
@@ -108,11 +108,11 @@ static void __sort_chain_graph_abs(struct callchain_node *node,
 }
 
 static void
-sort_chain_graph_abs(struct rb_root *rb_root, struct callchain_node *chain_root,
+sort_chain_graph_abs(struct rb_root *rb_root, struct callchain_root *chain_root,
                      u64 min_hit, struct callchain_param *param __used)
 {
-        __sort_chain_graph_abs(chain_root, min_hit);
-        rb_root->rb_node = chain_root->rb_root.rb_node;
+        __sort_chain_graph_abs(&chain_root->node, min_hit);
+        rb_root->rb_node = chain_root->node.rb_root.rb_node;
 }
 
 static void __sort_chain_graph_rel(struct callchain_node *node,
@@ -133,11 +133,11 @@ static void __sort_chain_graph_rel(struct callchain_node *node,
 }
 
 static void
-sort_chain_graph_rel(struct rb_root *rb_root, struct callchain_node *chain_root,
+sort_chain_graph_rel(struct rb_root *rb_root, struct callchain_root *chain_root,
                      u64 min_hit __used, struct callchain_param *param)
 {
-        __sort_chain_graph_rel(chain_root, param->min_percent / 100.0);
-        rb_root->rb_node = chain_root->rb_root.rb_node;
+        __sort_chain_graph_rel(&chain_root->node, param->min_percent / 100.0);
+        rb_root->rb_node = chain_root->node.rb_root.rb_node;
 }
 
 int register_callchain_param(struct callchain_param *param)
@@ -380,7 +380,7 @@ static void filter_context(struct ip_callchain *old, struct resolved_chain *new,
 }
 
 
-int append_chain(struct callchain_node *root, struct ip_callchain *chain,
+int append_chain(struct callchain_root *root, struct ip_callchain *chain,
                  struct map_symbol *syms, u64 period)
 {
         struct resolved_chain *filtered;
@@ -398,7 +398,10 @@ int append_chain(struct callchain_node *root, struct ip_callchain *chain,
         if (!filtered->nr)
                 goto end;
 
-        __append_chain_children(root, filtered, 0, period);
+        __append_chain_children(&root->node, filtered, 0, period);
+
+        if (filtered->nr > root->max_depth)
+                root->max_depth = filtered->nr;
 end:
         free(filtered);