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Commit 1096c35a authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
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perf ftrace: Add -D option for depth filter 



The -D/--graph-depth option is to set max graph depth.  The following
example traces max 2-depth of page fault handler.

  $ sudo perf ftrace -G __do_page_fault -D 2 -- hello
   ...
   0)               |  __do_page_fault() {
   0)   0.063 us    |    down_read_trylock();
   0)   0.251 us    |    find_vma();
   0)   5.374 us    |    handle_mm_fault();
   0)   0.054 us    |    up_read();
   0)   7.463 us    |  }
   ...

Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20170618142302.25390-4-namhyung@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 78b83e8b

tools/perf/Documentation/perf-ftrace.txt

+3 −0
Original line number Diff line number Diff line
@@ -78,6 +78,9 @@ OPTIONS 
	This can be used more than once to specify multiple functions.

	It will be passed to 'set_graph_notrace' in tracefs.



-D::

--graph-depth=::

	Set max depth for function graph tracer to follow



SEE ALSO

--------

tools/perf/builtin-ftrace.c

+31 −0
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ struct perf_ftrace { 
	struct list_head	notrace;

	struct list_head	graph_funcs;

	struct list_head	nograph_funcs;

	int			graph_depth;

};



struct filter_entry {
@@ -129,6 +130,9 @@ static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused) 
	if (reset_tracing_cpu() < 0)

		return -1;



	if (write_tracing_file("max_graph_depth", "0") < 0)

		return -1;



	reset_tracing_filters();

	return 0;

}
@@ -237,6 +241,26 @@ static void reset_tracing_filters(void) 
	write_tracing_file("set_graph_notrace", " ");

}



static int set_tracing_depth(struct perf_ftrace *ftrace)

{

	char buf[16];



	if (ftrace->graph_depth == 0)

		return 0;



	if (ftrace->graph_depth < 0) {

		pr_err("invalid graph depth: %d\n", ftrace->graph_depth);

		return -1;

	}



	snprintf(buf, sizeof(buf), "%d", ftrace->graph_depth);



	if (write_tracing_file("max_graph_depth", buf) < 0)

		return -1;



	return 0;

}



static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)

{

	char *trace_file;
@@ -284,6 +308,11 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv) 
		goto out_reset;

	}



	if (set_tracing_depth(ftrace) < 0) {

		pr_err("failed to set graph depth\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;
@@ -425,6 +454,8 @@ int cmd_ftrace(int argc, const char **argv) 
		     "Set graph filter on given functions", parse_filter_func),

	OPT_CALLBACK('g', "nograph-funcs", &ftrace.nograph_funcs, "func",

		     "Set nograph filter on given functions", parse_filter_func),

	OPT_INTEGER('D', "graph-depth", &ftrace.graph_depth,

		    "Max depth for function graph tracer"),

	OPT_END()

	};