perf top: Decay periods in callchains

It missed to decay periods in callchains when decaying hist entries.
This resulted in more than 100 percent overhead in callchains in the
fractal style output.

Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1451963160-17196-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 564377d2bebf3ee1c11d26839f68e42d7ad6b62f..53c43eb9489e4ba4a4e56a795bc05c2b85fb4cbc 100644 (file)
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -925,6 +925,34 @@ void free_callchain(struct callchain_root *root)
        free_callchain_node(&root->node);
 }
 
+static u64 decay_callchain_node(struct callchain_node *node)
+{
+       struct callchain_node *child;
+       struct rb_node *n;
+       u64 child_hits = 0;
+
+       n = rb_first(&node->rb_root_in);
+       while (n) {
+               child = container_of(n, struct callchain_node, rb_node_in);
+
+               child_hits += decay_callchain_node(child);
+               n = rb_next(n);
+       }
+
+       node->hit = (node->hit * 7) / 8;
+       node->children_hit = child_hits;
+
+       return node->hit;
+}
+
+void decay_callchain(struct callchain_root *root)
+{
+       if (!symbol_conf.use_callchain)
+               return;
+
+       decay_callchain_node(&root->node);
+}
+
 int callchain_node__make_parent_list(struct callchain_node *node)
 {
        struct callchain_node *parent = node->parent;

diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
index 8ac8f043004c792c4f265049ec85c1fcc4c3225a..18dd22269764cfe29e34964e02f70b5d1f77831d 100644 (file)
--- a/tools/perf/util/callchain.h
+++ b/tools/perf/util/callchain.h
@@ -253,6 +253,7 @@ int callchain_node__fprintf_value(struct callchain_node *node,
                                  FILE *fp, u64 total);
 
 void free_callchain(struct callchain_root *root);
+void decay_callchain(struct callchain_root *root);
 int callchain_node__make_parent_list(struct callchain_node *node);
 
 #endif /* __PERF_CALLCHAIN_H */

diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index afc9b8f1b36cac095cc068232ae81be78c0e767b..888776b43cb0ec8777f1711e229d467febb5bdac 100644 (file)
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -254,6 +254,7 @@ static bool hists__decay_entry(struct hists *hists, struct hist_entry *he)
        he_stat__decay(&he->stat);
        if (symbol_conf.cumulate_callchain)
                he_stat__decay(he->stat_acc);
+       decay_callchain(he->callchain);
 
        diff = prev_period - he->stat.period;