perf ftrace: Add support for trace option sleep-time

This adds an option '--graph-opts nosleep-time' which allow us only to
measure on-CPU time. This option is function_graph tracer only.
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-10-changbin.du@gmail.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-ftrace.txt

@@ -101,6 +101,10 @@ OPTIONS
 --graph-depth=::
 	Set max depth for function graph tracer to follow
 
+--graph-opts::
+	List of options allowed to set:
+	  nosleep-time - Measure on-CPU time only for function_graph tracer.
+
 SEE ALSO
 --------
 linkperf:perf-record[1], linkperf:perf-trace[1]

tools/perf/builtin-ftrace.c

@@ -44,6 +44,7 @@ struct perf_ftrace {
 	unsigned long		percpu_buffer_size;
 	bool			inherit;
 	int			func_stack_trace;
+	int			graph_nosleep_time;
 };
 
 struct filter_entry {
@@ -205,6 +206,7 @@ static void reset_tracing_options(struct perf_ftrace *ftrace __maybe_unused)
 {
 	write_tracing_option_file("function-fork", "0");
 	write_tracing_option_file("func_stack_trace", "0");
+	write_tracing_option_file("sleep-time", "1");
 }
 
 static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
@@ -386,6 +388,17 @@ static int set_tracing_trace_inherit(struct perf_ftrace *ftrace)
 	return 0;
 }
 
+static int set_tracing_sleep_time(struct perf_ftrace *ftrace)
+{
+	if (!ftrace->graph_nosleep_time)
+		return 0;
+
+	if (write_tracing_option_file("sleep-time", "0") < 0)
+		return -1;
+
+	return 0;
+}
+
 static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
 {
 	char *trace_file;
@@ -465,6 +478,11 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
 		goto out_reset;
 	}
 
+	if (set_tracing_sleep_time(ftrace) < 0) {
+		pr_err("failed to set tracing option sleep-time\n");
+		goto out_reset;
+	}
+
 	if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {
 		pr_err("failed to set current_tracer to %s\n", ftrace->tracer);
 		goto out_reset;
@@ -637,6 +655,26 @@ static int parse_func_tracer_opts(const struct option *opt,
 	return 0;
 }
 
+static int parse_graph_tracer_opts(const struct option *opt,
+				  const char *str, int unset)
+{
+	int ret;
+	struct perf_ftrace *ftrace = (struct perf_ftrace *) opt->value;
+	struct sublevel_option graph_tracer_opts[] = {
+		{ .name = "nosleep-time",	.value_ptr = &ftrace->graph_nosleep_time },
+		{ .name = NULL, }
+	};
+
+	if (unset)
+		return 0;
+
+	ret = perf_parse_sublevel_options(str, graph_tracer_opts);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
 static void select_tracer(struct perf_ftrace *ftrace)
 {
 	bool graph = !list_empty(&ftrace->graph_funcs) ||
@@ -694,6 +732,9 @@ int cmd_ftrace(int argc, const char **argv)
 		     "Set nograph filter on given functions", parse_filter_func),
 	OPT_INTEGER('D', "graph-depth", &ftrace.graph_depth,
 		    "Max depth for function graph tracer"),
+	OPT_CALLBACK(0, "graph-opts", &ftrace, "options",
+		     "graph tracer options, available options: nosleep-time",
+		     parse_graph_tracer_opts),
 	OPT_CALLBACK('m', "buffer-size", &ftrace.percpu_buffer_size, "size",
 		     "size of per cpu buffer", parse_buffer_size),
 	OPT_BOOLEAN(0, "inherit", &ftrace.inherit,