perf_counter tools: Set the minimum percent for callchains to be displayed

Callchains output may become a burden on a trace because even
rarely hit site are exposed. This can be too much information.

Let the user set a threshold as a minimum percent of hits using
the new pattern for the -c option:

    -c mode,min_percent

Example:

$ perf report -s sym -c flat,4

     8.25%  [k] copy_user_generic_string
             4.19%
                copy_user_generic_string
                generic_file_aio_read
                do_sync_read
                vfs_read
                sys_pread64
                system_call_fastpath
                pread64

     5.39%  [k] search_by_key
     4.63%  0x00000000009e0a
     2.36%  [k] memcpy_c
[...]

$ perf report -s sym -c graph,2

     8.25%  [k] copy_user_generic_string
                |
                |--4.31%-- generic_file_aio_read
                |          do_sync_read
                |          vfs_read
                |          |
                |           --4.19%-- sys_pread64
                |                     system_call_fastpath
                |                     pread64
                |
                 --3.24%-- generic_file_buffered_write
                           __generic_file_aio_write_nolock
                           generic_file_aio_write
                           do_sync_write
                           reiserfs_file_write
                           vfs_write
                           |
                            --3.14%-- sys_pwrite64
                                      system_call_fastpath
                                      __pwrite64

     5.39%  [k] search_by_key
                |
                 --2.23%-- reiserfs_update_sd_size

     4.63%  0x00000000009e0a

     2.36%  [k] memcpy_c
[...]

You can also omit it and it will default to 0.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <1246558475-10624-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 15 insertions, 10 deletions

diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index a9873aafcd92..c9900fe6b8b4 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -57,18 +57,19 @@ rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
  * Once we get every callchains from the stream, we can now
  * sort them by hit
  */
-void sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node)
+void sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
+		     u64 min_hit)
 {
 	struct callchain_node *child;
 
 	chain_for_each_child(child, node)
-		sort_chain_flat(rb_root, child);
+		sort_chain_flat(rb_root, child, min_hit);
 
-	if (node->hit)
+	if (node->hit && node->hit >= min_hit)
 		rb_insert_callchain(rb_root, node, FLAT);
 }
 
-static void __sort_chain_graph(struct callchain_node *node)
+static void __sort_chain_graph(struct callchain_node *node, u64 min_hit)
 {
 	struct callchain_node *child;
 
@@ -76,16 +77,18 @@ static void __sort_chain_graph(struct callchain_node *node)
 	node->cumul_hit = node->hit;
 
 	chain_for_each_child(child, node) {
-		__sort_chain_graph(child);
-		rb_insert_callchain(&node->rb_root, child, GRAPH);
+		__sort_chain_graph(child, min_hit);
+		if (child->cumul_hit >= min_hit)
+			rb_insert_callchain(&node->rb_root, child, GRAPH);
 		node->cumul_hit += child->cumul_hit;
 	}
 }
 
 void
-sort_chain_graph(struct rb_root *rb_root, struct callchain_node *chain_root)
+sort_chain_graph(struct rb_root *rb_root, struct callchain_node *chain_root,
+		 u64 min_hit)
 {
-	__sort_chain_graph(chain_root);
+	__sort_chain_graph(chain_root, min_hit);
 	rb_root->rb_node = chain_root->rb_root.rb_node;
 }
 
diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
index dfa56008d9ad..f3e4776e7430 100644
--- a/tools/perf/util/callchain.h
+++ b/tools/perf/util/callchain.h
@@ -38,6 +38,8 @@ static inline void callchain_init(struct callchain_node *node)
 
 void append_chain(struct callchain_node *root, struct ip_callchain *chain,
 		  struct symbol **syms);
-void sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node);
-void sort_chain_graph(struct rb_root *rb_root, struct callchain_node *node);
+void sort_chain_flat(struct rb_root *rb_root, struct callchain_node *node,
+		     u64 min_hit);
+void sort_chain_graph(struct rb_root *rb_root, struct callchain_node *node,
+		      u64 min_hit);
 #endif