[PATCH] perf tools: Fix cumul hit based sub-total

[PATCH] perf tools: Fix cumul hit based sub-total

[Frederic Weisbecker]

The callchain fractal mode builds each new total hits in a new branch
of profiling by using the parent's hits of the current branch plus the
hits of the children.

This is wrong, the total hits of a branch should be made of the sum of
every children hits, we must ignore the parent hits in this scope.

This patch also fixes another mistakes with the hit counting.

Now the rates are corrects.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
---
 tools/perf/builtin-report.c |    4 ++--
 tools/perf/util/callchain.c |   27 ++++++++++++++++-----------
 tools/perf/util/callchain.h |    7 ++++++-
 3 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 8cb58d6..da402e1 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -901,7 +901,7 @@ callchain__fprintf_graph(FILE *fp, struct callchain_node *self,
 	int i;
 
 	if (callchain_param.mode == CHAIN_GRAPH_REL)
-		new_total = self->cumul_hit;
+		new_total = self->children_hit;
 	else
 		new_total = total_samples;
 
@@ -930,7 +930,7 @@ callchain__fprintf_graph(FILE *fp, struct callchain_node *self,
 			ret += ipchain__fprintf_graph(fp, chain, depth,
 						      new_depth_mask, i++,
 						      new_total,
-						      child->cumul_hit);
+						      cumul_hits(child));
 		}
 		ret += callchain__fprintf_graph(fp, child, new_total,
 						depth + 1,
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 9d3c814..98c5627 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -26,10 +26,14 @@ rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
 	struct rb_node **p = &root->rb_node;
 	struct rb_node *parent = NULL;
 	struct callchain_node *rnode;
+	u64 chain_cumul = cumul_hits(chain);
 
 	while (*p) {
+		u64 rnode_cumul;
+
 		parent = *p;
 		rnode = rb_entry(parent, struct callchain_node, rb_node);
+		rnode_cumul = cumul_hits(rnode);
 
 		switch (mode) {
 		case CHAIN_FLAT:
@@ -40,7 +44,7 @@ rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
 			break;
 		case CHAIN_GRAPH_ABS: /* Falldown */
 		case CHAIN_GRAPH_REL:
-			if (rnode->cumul_hit < chain->cumul_hit)
+			if (rnode_cumul < chain_cumul)
 				p = &(*p)->rb_left;
 			else
 				p = &(*p)->rb_right;
@@ -87,7 +91,7 @@ static void __sort_chain_graph_abs(struct callchain_node *node,
 
 	chain_for_each_child(child, node) {
 		__sort_chain_graph_abs(child, min_hit);
-		if (child->cumul_hit >= min_hit)
+		if (cumul_hits(child) >= min_hit)
 			rb_insert_callchain(&node->rb_root, child,
 					    CHAIN_GRAPH_ABS);
 	}
@@ -108,11 +112,11 @@ static void __sort_chain_graph_rel(struct callchain_node *node,
 	u64 min_hit;
 
 	node->rb_root = RB_ROOT;
-	min_hit = node->cumul_hit * min_percent / 100.0;
+	min_hit = node->children_hit * min_percent / 100.0;
 
 	chain_for_each_child(child, node) {
 		__sort_chain_graph_rel(child, min_percent);
-		if (child->cumul_hit >= min_hit)
+		if (cumul_hits(child) >= min_hit)
 			rb_insert_callchain(&node->rb_root, child,
 					    CHAIN_GRAPH_REL);
 	}
@@ -211,7 +215,8 @@ add_child(struct callchain_node *parent, struct ip_callchain *chain,
 	new = create_child(parent, false);
 	fill_node(new, chain, start, syms);
 
-	new->cumul_hit = new->hit = 1;
+	new->children_hit = 0;
+	new->hit = 1;
 }
 
 /*
@@ -241,7 +246,8 @@ split_add_child(struct callchain_node *parent, struct ip_callchain *chain,
 
 	/* split the hits */
 	new->hit = parent->hit;
-	new->cumul_hit = parent->cumul_hit;
+	new->children_hit = parent->children_hit;
+	parent->children_hit = cumul_hits(new);
 	new->val_nr = parent->val_nr - idx_local;
 	parent->val_nr = idx_local;
 
@@ -249,6 +255,7 @@ split_add_child(struct callchain_node *parent, struct ip_callchain *chain,
 	if (idx_total < chain->nr) {
 		parent->hit = 0;
 		add_child(parent, chain, idx_total, syms);
+		parent->children_hit++;
 	} else {
 		parent->hit = 1;
 	}
@@ -269,13 +276,13 @@ __append_chain_children(struct callchain_node *root, struct ip_callchain *chain,
 		unsigned int ret = __append_chain(rnode, chain, start, syms);
 
 		if (!ret)
-			goto cumul;
+			goto inc_children_hit;
 	}
 	/* nothing in children, add to the current node */
 	add_child(root, chain, start, syms);
 
-cumul:
-	root->cumul_hit++;
+inc_children_hit:
+	root->children_hit++;
 }
 
 static int
@@ -317,8 +324,6 @@ __append_chain(struct callchain_node *root, struct ip_callchain *chain,
 	/* we match 100% of the path, increment the hit */
 	if (i - start == root->val_nr && i == chain->nr) {
 		root->hit++;
-		root->cumul_hit++;
-
 		return 0;
 	}
 
diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
index 7812122..b2d128e 100644
--- a/tools/perf/util/callchain.h
+++ b/tools/perf/util/callchain.h
@@ -21,7 +21,7 @@ struct callchain_node {
 	struct rb_root		rb_root; /* sorted tree of children */
 	unsigned int		val_nr;
 	u64			hit;
-	u64			cumul_hit; /* hit + hits of children */
+	u64			children_hit;
 };
 
 struct callchain_param;
@@ -48,6 +48,11 @@ static inline void callchain_init(struct callchain_node *node)
 	INIT_LIST_HEAD(&node->val);
 }
 
+static inline u64 cumul_hits(struct callchain_node *node)
+{
+	return node->hit + node->children_hit;
+}
+
 int register_callchain_param(struct callchain_param *param);
 void append_chain(struct callchain_node *root, struct ip_callchain *chain,
 		  struct symbol **syms);
-- 
1.6.2.3

[tip:perfcounters/urgent] perf tools: Fix call-chain cumul hit based sub-total (fractal mode)

[tip-bot for Frederic Weisbecker]

Commit-ID:  a4f975e96df471507588739ecbf981678c67552d
Gitweb:     http://git.kernel.org/tip/a4f975e96df471507588739ecbf981678c67552d
Author:     Frederic Weisbecker <fweisbec@gmail.com>
AuthorDate: Fri, 7 Aug 2009 07:11:05 +0200
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 7 Aug 2009 08:32:54 +0200

perf tools: Fix call-chain cumul hit based sub-total (fractal mode)

The callchain fractal mode builds each new total hits in a new
branch of profiling by using the parent's hits of the current
branch plus the hits of the children.

This is wrong, the total hits of a branch should be made of the
sum of every children hits, we must ignore the parent hits in
this scope.

This patch also fixes another mistake with the hit counting.

Now the rates are correct.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <1249621865-9325-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>


---
 tools/perf/builtin-report.c |    4 ++--
 tools/perf/util/callchain.c |   27 ++++++++++++++++-----------
 tools/perf/util/callchain.h |    7 ++++++-
 3 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 8cb58d6..da402e1 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -901,7 +901,7 @@ callchain__fprintf_graph(FILE *fp, struct callchain_node *self,
 	int i;
 
 	if (callchain_param.mode == CHAIN_GRAPH_REL)
-		new_total = self->cumul_hit;
+		new_total = self->children_hit;
 	else
 		new_total = total_samples;
 
@@ -930,7 +930,7 @@ callchain__fprintf_graph(FILE *fp, struct callchain_node *self,
 			ret += ipchain__fprintf_graph(fp, chain, depth,
 						      new_depth_mask, i++,
 						      new_total,
-						      child->cumul_hit);
+						      cumul_hits(child));
 		}
 		ret += callchain__fprintf_graph(fp, child, new_total,
 						depth + 1,
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 9d3c814..98c5627 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -26,10 +26,14 @@ rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
 	struct rb_node **p = &root->rb_node;
 	struct rb_node *parent = NULL;
 	struct callchain_node *rnode;
+	u64 chain_cumul = cumul_hits(chain);
 
 	while (*p) {
+		u64 rnode_cumul;
+
 		parent = *p;
 		rnode = rb_entry(parent, struct callchain_node, rb_node);
+		rnode_cumul = cumul_hits(rnode);
 
 		switch (mode) {
 		case CHAIN_FLAT:
@@ -40,7 +44,7 @@ rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
 			break;
 		case CHAIN_GRAPH_ABS: /* Falldown */
 		case CHAIN_GRAPH_REL:
-			if (rnode->cumul_hit < chain->cumul_hit)
+			if (rnode_cumul < chain_cumul)
 				p = &(*p)->rb_left;
 			else
 				p = &(*p)->rb_right;
@@ -87,7 +91,7 @@ static void __sort_chain_graph_abs(struct callchain_node *node,
 
 	chain_for_each_child(child, node) {
 		__sort_chain_graph_abs(child, min_hit);
-		if (child->cumul_hit >= min_hit)
+		if (cumul_hits(child) >= min_hit)
 			rb_insert_callchain(&node->rb_root, child,
 					    CHAIN_GRAPH_ABS);
 	}
@@ -108,11 +112,11 @@ static void __sort_chain_graph_rel(struct callchain_node *node,
 	u64 min_hit;
 
 	node->rb_root = RB_ROOT;
-	min_hit = node->cumul_hit * min_percent / 100.0;
+	min_hit = node->children_hit * min_percent / 100.0;
 
 	chain_for_each_child(child, node) {
 		__sort_chain_graph_rel(child, min_percent);
-		if (child->cumul_hit >= min_hit)
+		if (cumul_hits(child) >= min_hit)
 			rb_insert_callchain(&node->rb_root, child,
 					    CHAIN_GRAPH_REL);
 	}
@@ -211,7 +215,8 @@ add_child(struct callchain_node *parent, struct ip_callchain *chain,
 	new = create_child(parent, false);
 	fill_node(new, chain, start, syms);
 
-	new->cumul_hit = new->hit = 1;
+	new->children_hit = 0;
+	new->hit = 1;
 }
 
 /*
@@ -241,7 +246,8 @@ split_add_child(struct callchain_node *parent, struct ip_callchain *chain,
 
 	/* split the hits */
 	new->hit = parent->hit;
-	new->cumul_hit = parent->cumul_hit;
+	new->children_hit = parent->children_hit;
+	parent->children_hit = cumul_hits(new);
 	new->val_nr = parent->val_nr - idx_local;
 	parent->val_nr = idx_local;
 
@@ -249,6 +255,7 @@ split_add_child(struct callchain_node *parent, struct ip_callchain *chain,
 	if (idx_total < chain->nr) {
 		parent->hit = 0;
 		add_child(parent, chain, idx_total, syms);
+		parent->children_hit++;
 	} else {
 		parent->hit = 1;
 	}
@@ -269,13 +276,13 @@ __append_chain_children(struct callchain_node *root, struct ip_callchain *chain,
 		unsigned int ret = __append_chain(rnode, chain, start, syms);
 
 		if (!ret)
-			goto cumul;
+			goto inc_children_hit;
 	}
 	/* nothing in children, add to the current node */
 	add_child(root, chain, start, syms);
 
-cumul:
-	root->cumul_hit++;
+inc_children_hit:
+	root->children_hit++;
 }
 
 static int
@@ -317,8 +324,6 @@ __append_chain(struct callchain_node *root, struct ip_callchain *chain,
 	/* we match 100% of the path, increment the hit */
 	if (i - start == root->val_nr && i == chain->nr) {
 		root->hit++;
-		root->cumul_hit++;
-
 		return 0;
 	}
 
diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
index 7812122..b2d128e 100644
--- a/tools/perf/util/callchain.h
+++ b/tools/perf/util/callchain.h
@@ -21,7 +21,7 @@ struct callchain_node {
 	struct rb_root		rb_root; /* sorted tree of children */
 	unsigned int		val_nr;
 	u64			hit;
-	u64			cumul_hit; /* hit + hits of children */
+	u64			children_hit;
 };
 
 struct callchain_param;
@@ -48,6 +48,11 @@ static inline void callchain_init(struct callchain_node *node)
 	INIT_LIST_HEAD(&node->val);
 }
 
+static inline u64 cumul_hits(struct callchain_node *node)
+{
+	return node->hit + node->children_hit;
+}
+
 int register_callchain_param(struct callchain_param *param);
 void append_chain(struct callchain_node *root, struct ip_callchain *chain,
 		  struct symbol **syms);

[tip:perfcounters/urgent] perf tools: Fix call-chain cumul hit based sub-total (fractal mode)

[tip-bot for Frederic Weisbecker]

Commit-ID:  35281b7c4d6f4ae33e6c3e3b0920e86a99c60aa2
Gitweb:     http://git.kernel.org/tip/35281b7c4d6f4ae33e6c3e3b0920e86a99c60aa2
Author:     Frederic Weisbecker <fweisbec@gmail.com>
AuthorDate: Fri, 7 Aug 2009 07:11:05 +0200
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 7 Aug 2009 09:37:23 +0200

perf tools: Fix call-chain cumul hit based sub-total (fractal mode)

The callchain fractal mode builds each new total hits in a new
branch of profiling by using the parent's hits of the current
branch plus the hits of the children.

This is wrong, the total hits of a branch should be made of the
sum of every children hits, we must ignore the parent hits in
this scope.

This patch also fixes another mistake with the hit counting.

Now the rates are correct.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <1249621865-9325-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>


---
 tools/perf/builtin-report.c |    4 ++--
 tools/perf/util/callchain.c |   27 ++++++++++++++++-----------
 tools/perf/util/callchain.h |    7 ++++++-
 3 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 8cb58d6..da402e1 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -901,7 +901,7 @@ callchain__fprintf_graph(FILE *fp, struct callchain_node *self,
 	int i;
 
 	if (callchain_param.mode == CHAIN_GRAPH_REL)
-		new_total = self->cumul_hit;
+		new_total = self->children_hit;
 	else
 		new_total = total_samples;
 
@@ -930,7 +930,7 @@ callchain__fprintf_graph(FILE *fp, struct callchain_node *self,
 			ret += ipchain__fprintf_graph(fp, chain, depth,
 						      new_depth_mask, i++,
 						      new_total,
-						      child->cumul_hit);
+						      cumul_hits(child));
 		}
 		ret += callchain__fprintf_graph(fp, child, new_total,
 						depth + 1,
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 9d3c814..98c5627 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -26,10 +26,14 @@ rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
 	struct rb_node **p = &root->rb_node;
 	struct rb_node *parent = NULL;
 	struct callchain_node *rnode;
+	u64 chain_cumul = cumul_hits(chain);
 
 	while (*p) {
+		u64 rnode_cumul;
+
 		parent = *p;
 		rnode = rb_entry(parent, struct callchain_node, rb_node);
+		rnode_cumul = cumul_hits(rnode);
 
 		switch (mode) {
 		case CHAIN_FLAT:
@@ -40,7 +44,7 @@ rb_insert_callchain(struct rb_root *root, struct callchain_node *chain,
 			break;
 		case CHAIN_GRAPH_ABS: /* Falldown */
 		case CHAIN_GRAPH_REL:
-			if (rnode->cumul_hit < chain->cumul_hit)
+			if (rnode_cumul < chain_cumul)
 				p = &(*p)->rb_left;
 			else
 				p = &(*p)->rb_right;
@@ -87,7 +91,7 @@ static void __sort_chain_graph_abs(struct callchain_node *node,
 
 	chain_for_each_child(child, node) {
 		__sort_chain_graph_abs(child, min_hit);
-		if (child->cumul_hit >= min_hit)
+		if (cumul_hits(child) >= min_hit)
 			rb_insert_callchain(&node->rb_root, child,
 					    CHAIN_GRAPH_ABS);
 	}
@@ -108,11 +112,11 @@ static void __sort_chain_graph_rel(struct callchain_node *node,
 	u64 min_hit;
 
 	node->rb_root = RB_ROOT;
-	min_hit = node->cumul_hit * min_percent / 100.0;
+	min_hit = node->children_hit * min_percent / 100.0;
 
 	chain_for_each_child(child, node) {
 		__sort_chain_graph_rel(child, min_percent);
-		if (child->cumul_hit >= min_hit)
+		if (cumul_hits(child) >= min_hit)
 			rb_insert_callchain(&node->rb_root, child,
 					    CHAIN_GRAPH_REL);
 	}
@@ -211,7 +215,8 @@ add_child(struct callchain_node *parent, struct ip_callchain *chain,
 	new = create_child(parent, false);
 	fill_node(new, chain, start, syms);
 
-	new->cumul_hit = new->hit = 1;
+	new->children_hit = 0;
+	new->hit = 1;
 }
 
 /*
@@ -241,7 +246,8 @@ split_add_child(struct callchain_node *parent, struct ip_callchain *chain,
 
 	/* split the hits */
 	new->hit = parent->hit;
-	new->cumul_hit = parent->cumul_hit;
+	new->children_hit = parent->children_hit;
+	parent->children_hit = cumul_hits(new);
 	new->val_nr = parent->val_nr - idx_local;
 	parent->val_nr = idx_local;
 
@@ -249,6 +255,7 @@ split_add_child(struct callchain_node *parent, struct ip_callchain *chain,
 	if (idx_total < chain->nr) {
 		parent->hit = 0;
 		add_child(parent, chain, idx_total, syms);
+		parent->children_hit++;
 	} else {
 		parent->hit = 1;
 	}
@@ -269,13 +276,13 @@ __append_chain_children(struct callchain_node *root, struct ip_callchain *chain,
 		unsigned int ret = __append_chain(rnode, chain, start, syms);
 
 		if (!ret)
-			goto cumul;
+			goto inc_children_hit;
 	}
 	/* nothing in children, add to the current node */
 	add_child(root, chain, start, syms);
 
-cumul:
-	root->cumul_hit++;
+inc_children_hit:
+	root->children_hit++;
 }
 
 static int
@@ -317,8 +324,6 @@ __append_chain(struct callchain_node *root, struct ip_callchain *chain,
 	/* we match 100% of the path, increment the hit */
 	if (i - start == root->val_nr && i == chain->nr) {
 		root->hit++;
-		root->cumul_hit++;
-
 		return 0;
 	}
 
diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
index 7812122..b2d128e 100644
--- a/tools/perf/util/callchain.h
+++ b/tools/perf/util/callchain.h
@@ -21,7 +21,7 @@ struct callchain_node {
 	struct rb_root		rb_root; /* sorted tree of children */
 	unsigned int		val_nr;
 	u64			hit;
-	u64			cumul_hit; /* hit + hits of children */
+	u64			children_hit;
 };
 
 struct callchain_param;
@@ -48,6 +48,11 @@ static inline void callchain_init(struct callchain_node *node)
 	INIT_LIST_HEAD(&node->val);
 }
 
+static inline u64 cumul_hits(struct callchain_node *node)
+{
+	return node->hit + node->children_hit;
+}
+
 int register_callchain_param(struct callchain_param *param);
 void append_chain(struct callchain_node *root, struct ip_callchain *chain,
 		  struct symbol **syms);

Re: [PATCH] perf tools: Fix cumul hit based sub-total

[Peter Zijlstra]

On Fri, 2009-08-07 at 07:11 +0200, Frederic Weisbecker wrote:
> The callchain fractal mode builds each new total hits in a new branch
> of profiling by using the parent's hits of the current branch plus the
> hits of the children.
> 
> This is wrong, the total hits of a branch should be made of the sum of
> every children hits, we must ignore the parent hits in this scope.
> 
> This patch also fixes another mistakes with the hit counting.
> 
> Now the rates are corrects.
> 
> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Mike Galbraith <efault@gmx.de>
> ---

Ah will this fix these instances where you'd have things like

                |                     page_fault
                |                     |
                |                     |--100.00%-- __strcmp_sse2
                |                     |          copy_dep_chain
                |                     |          __libc_start_main
                |                     |
                |                      --100.00%-- gettimeofday
                |                                __libc_start_main


I was meaning to poke you about that :-)

Re: [PATCH] perf tools: Fix cumul hit based sub-total

[Frederic Weisbecker]

On Fri, Aug 07, 2009 at 10:12:58AM +0200, Peter Zijlstra wrote:
> On Fri, 2009-08-07 at 07:11 +0200, Frederic Weisbecker wrote:
> > The callchain fractal mode builds each new total hits in a new branch
> > of profiling by using the parent's hits of the current branch plus the
> > hits of the children.
> > 
> > This is wrong, the total hits of a branch should be made of the sum of
> > every children hits, we must ignore the parent hits in this scope.
> > 
> > This patch also fixes another mistakes with the hit counting.
> > 
> > Now the rates are corrects.
> > 
> > Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
> > Cc: Peter Zijlstra <peterz@infradead.org>
> > Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> > Cc: Peter Zijlstra <peterz@infradead.org>
> > Cc: Mike Galbraith <efault@gmx.de>
> > ---
> 
> Ah will this fix these instances where you'd have things like
> 
>                 |                     page_fault
>                 |                     |
>                 |                     |--100.00%-- __strcmp_sse2
>                 |                     |          copy_dep_chain
>                 |                     |          __libc_start_main
>                 |                     |
>                 |                      --100.00%-- gettimeofday
>                 |                                __libc_start_main



I haven't met such huge rate's mistake yet :)
It was more about +-20% of imprecision.

I guess this patch should fix what you've met. If you still see that,
please tell me.

BTW, I will soon add a debug option to check the percentage correctness
and things like that...