trace: add non-hierarchical function_graph option

Add the 'funcgraph-flat' option to the function_graph tracer to use the default
trace printing format rather than the hierarchical formatting normally used.

Change-Id: If2900bfb86e6f8f51379f56da4f6fabafa630909
Signed-off-by: Jamie Gennis <jgennis@google.com>

Documentation/trace/ftrace.txt

@@ -2088,6 +2088,35 @@ will produce:
  1)   1.449 us    |             }
 
 
+You can disable the hierarchical function call formatting and instead print a
+flat list of function entry and return events.  This uses the format described
+in the Output Formatting section and respects all the trace options that
+control that formatting.  Hierarchical formatting is the default.
+
+	hierachical: echo nofuncgraph-flat > trace_options
+	flat: echo funcgraph-flat > trace_options
+
+  ie:
+
+  # tracer: function_graph
+  #
+  # entries-in-buffer/entries-written: 68355/68355   #P:2
+  #
+  #                              _-----=> irqs-off
+  #                             / _----=> need-resched
+  #                            | / _---=> hardirq/softirq
+  #                            || / _--=> preempt-depth
+  #                            ||| /     delay
+  #           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
+  #              | |       |   ||||       |         |
+                sh-1806  [001] d...   198.843443: graph_ent: func=_raw_spin_lock
+                sh-1806  [001] d...   198.843445: graph_ent: func=__raw_spin_lock
+                sh-1806  [001] d..1   198.843447: graph_ret: func=__raw_spin_lock
+                sh-1806  [001] d..1   198.843449: graph_ret: func=_raw_spin_lock
+                sh-1806  [001] d..1   198.843451: graph_ent: func=_raw_spin_unlock_irqrestore
+                sh-1806  [001] d...   198.843453: graph_ret: func=_raw_spin_unlock_irqrestore
+
+
 You might find other useful features for this tracer in the
 following "dynamic ftrace" section such as tracing only specific
 functions or tasks.

kernel/trace/trace_functions_graph.c

@@ -64,6 +64,9 @@ struct fgraph_data {
 
 #define TRACE_GRAPH_INDENT	2
 
+/* Flag options */
+#define TRACE_GRAPH_PRINT_FLAT		0x80
+
 static unsigned int max_depth;
 
 static struct tracer_opt trace_opts[] = {
@@ -87,6 +90,8 @@ static struct tracer_opt trace_opts[] = {
 	{ TRACER_OPT(sleep-time, TRACE_GRAPH_SLEEP_TIME) },
 	/* Include time within nested functions */
 	{ TRACER_OPT(graph-time, TRACE_GRAPH_GRAPH_TIME) },
+	/* Use standard trace formatting rather than hierarchical */
+	{ TRACER_OPT(funcgraph-flat, TRACE_GRAPH_PRINT_FLAT) },
 	{ } /* Empty entry */
 };
 
@@ -1165,6 +1170,9 @@ print_graph_function_flags(struct trace_iterator *iter, u32 flags)
 	int cpu = iter->cpu;
 	int ret;
 
+	if (flags & TRACE_GRAPH_PRINT_FLAT)
+		return TRACE_TYPE_UNHANDLED;
+
 	if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
 		per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
 		return TRACE_TYPE_HANDLED;
@@ -1222,13 +1230,6 @@ print_graph_function(struct trace_iterator *iter)
 	return print_graph_function_flags(iter, tracer_flags.val);
 }
 
-static enum print_line_t
-print_graph_function_event(struct trace_iterator *iter, int flags,
-			   struct trace_event *event)
-{
-	return print_graph_function(iter);
-}
-
 static void print_lat_header(struct seq_file *s, u32 flags)
 {
 	static const char spaces[] = "                "	/* 16 spaces */
@@ -1297,6 +1298,11 @@ void print_graph_headers_flags(struct seq_file *s, u32 flags)
 	struct trace_iterator *iter = s->private;
 	struct trace_array *tr = iter->tr;
 
+	if (flags & TRACE_GRAPH_PRINT_FLAT) {
+		trace_default_header(s);
+		return;
+	}
+
 	if (!(tr->trace_flags & TRACE_ITER_CONTEXT_INFO))
 		return;
 
@@ -1378,19 +1384,6 @@ func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
 	return 0;
 }
 
-static struct trace_event_functions graph_functions = {
-	.trace		= print_graph_function_event,
-};
-
-static struct trace_event graph_trace_entry_event = {
-	.type		= TRACE_GRAPH_ENT,
-	.funcs		= &graph_functions,
-};
-
-static struct trace_event graph_trace_ret_event = {
-	.type		= TRACE_GRAPH_RET,
-	.funcs		= &graph_functions
-};
 
 static struct tracer graph_trace __tracer_data = {
 	.name		= "function_graph",
@@ -1467,16 +1460,6 @@ static __init int init_graph_trace(void)
 {
 	max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
 
-	if (!register_trace_event(&graph_trace_entry_event)) {
-		pr_warning("Warning: could not register graph trace events\n");
-		return 1;
-	}
-
-	if (!register_trace_event(&graph_trace_ret_event)) {
-		pr_warning("Warning: could not register graph trace events\n");
-		return 1;
-	}
-
 	return register_tracer(&graph_trace);
 }
 

kernel/trace/trace_output.c

@@ -855,6 +855,168 @@ static struct trace_event trace_fn_event = {
 	.funcs		= &trace_fn_funcs,
 };
 
+/* TRACE_GRAPH_ENT */
+static enum print_line_t trace_graph_ent_trace(struct trace_iterator *iter, int flags,
+					struct trace_event *event)
+{
+	struct trace_seq *s = &iter->seq;
+	struct ftrace_graph_ent_entry *field;
+
+	trace_assign_type(field, iter->ent);
+
+	if (!trace_seq_puts(s, "graph_ent: func="))
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	if (!seq_print_ip_sym(s, field->graph_ent.func, flags))
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	if (!trace_seq_puts(s, "\n"))
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	return TRACE_TYPE_HANDLED;
+}
+
+static enum print_line_t trace_graph_ent_raw(struct trace_iterator *iter, int flags,
+				      struct trace_event *event)
+{
+	struct ftrace_graph_ent_entry *field;
+
+	trace_assign_type(field, iter->ent);
+
+	if (!trace_seq_printf(&iter->seq, "%lx %d\n",
+			      field->graph_ent.func,
+			      field->graph_ent.depth))
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	return TRACE_TYPE_HANDLED;
+}
+
+static enum print_line_t trace_graph_ent_hex(struct trace_iterator *iter, int flags,
+				      struct trace_event *event)
+{
+	struct ftrace_graph_ent_entry *field;
+	struct trace_seq *s = &iter->seq;
+
+	trace_assign_type(field, iter->ent);
+
+	SEQ_PUT_HEX_FIELD_RET(s, field->graph_ent.func);
+	SEQ_PUT_HEX_FIELD_RET(s, field->graph_ent.depth);
+
+	return TRACE_TYPE_HANDLED;
+}
+
+static enum print_line_t trace_graph_ent_bin(struct trace_iterator *iter, int flags,
+				      struct trace_event *event)
+{
+	struct ftrace_graph_ent_entry *field;
+	struct trace_seq *s = &iter->seq;
+
+	trace_assign_type(field, iter->ent);
+
+	SEQ_PUT_FIELD_RET(s, field->graph_ent.func);
+	SEQ_PUT_FIELD_RET(s, field->graph_ent.depth);
+
+	return TRACE_TYPE_HANDLED;
+}
+
+static struct trace_event_functions trace_graph_ent_funcs = {
+	.trace		= trace_graph_ent_trace,
+	.raw		= trace_graph_ent_raw,
+	.hex		= trace_graph_ent_hex,
+	.binary		= trace_graph_ent_bin,
+};
+
+static struct trace_event trace_graph_ent_event = {
+	.type		= TRACE_GRAPH_ENT,
+	.funcs		= &trace_graph_ent_funcs,
+};
+
+/* TRACE_GRAPH_RET */
+static enum print_line_t trace_graph_ret_trace(struct trace_iterator *iter, int flags,
+					struct trace_event *event)
+{
+	struct trace_seq *s = &iter->seq;
+	struct trace_entry *entry = iter->ent;
+	struct ftrace_graph_ret_entry *field;
+
+	trace_assign_type(field, entry);
+
+	if (!trace_seq_puts(s, "graph_ret: func="))
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	if (!seq_print_ip_sym(s, field->ret.func, flags))
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	if (!trace_seq_puts(s, "\n"))
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	return TRACE_TYPE_HANDLED;
+}
+
+static enum print_line_t trace_graph_ret_raw(struct trace_iterator *iter, int flags,
+				      struct trace_event *event)
+{
+	struct ftrace_graph_ret_entry *field;
+
+	trace_assign_type(field, iter->ent);
+
+	if (!trace_seq_printf(&iter->seq, "%lx %lld %lld %ld %d\n",
+			      field->ret.func,
+			      field->ret.calltime,
+			      field->ret.rettime,
+			      field->ret.overrun,
+			      field->ret.depth));
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	return TRACE_TYPE_HANDLED;
+}
+
+static enum print_line_t trace_graph_ret_hex(struct trace_iterator *iter, int flags,
+				      struct trace_event *event)
+{
+	struct ftrace_graph_ret_entry *field;
+	struct trace_seq *s = &iter->seq;
+
+	trace_assign_type(field, iter->ent);
+
+	SEQ_PUT_HEX_FIELD_RET(s, field->ret.func);
+	SEQ_PUT_HEX_FIELD_RET(s, field->ret.calltime);
+	SEQ_PUT_HEX_FIELD_RET(s, field->ret.rettime);
+	SEQ_PUT_HEX_FIELD_RET(s, field->ret.overrun);
+	SEQ_PUT_HEX_FIELD_RET(s, field->ret.depth);
+
+	return TRACE_TYPE_HANDLED;
+}
+
+static enum print_line_t trace_graph_ret_bin(struct trace_iterator *iter, int flags,
+				      struct trace_event *event)
+{
+	struct ftrace_graph_ret_entry *field;
+	struct trace_seq *s = &iter->seq;
+
+	trace_assign_type(field, iter->ent);
+
+	SEQ_PUT_FIELD_RET(s, field->ret.func);
+	SEQ_PUT_FIELD_RET(s, field->ret.calltime);
+	SEQ_PUT_FIELD_RET(s, field->ret.rettime);
+	SEQ_PUT_FIELD_RET(s, field->ret.overrun);
+	SEQ_PUT_FIELD_RET(s, field->ret.depth);
+
+	return TRACE_TYPE_HANDLED;
+}
+
+static struct trace_event_functions trace_graph_ret_funcs = {
+	.trace		= trace_graph_ret_trace,
+	.raw		= trace_graph_ret_raw,
+	.hex		= trace_graph_ret_hex,
+	.binary		= trace_graph_ret_bin,
+};
+
+static struct trace_event trace_graph_ret_event = {
+	.type		= TRACE_GRAPH_RET,
+	.funcs		= &trace_graph_ret_funcs,
+};
+
 /* TRACE_CTX an TRACE_WAKE */
 static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
 					     char *delim)
@@ -1232,6 +1394,8 @@ static struct trace_event trace_print_event = {
 
 static struct trace_event *events[] __initdata = {
 	&trace_fn_event,
+	&trace_graph_ent_event,
+	&trace_graph_ret_event,
 	&trace_ctx_event,
 	&trace_wake_event,
 	&trace_stack_event,