Commit d6d81bfe authored by Changbin Du's avatar Changbin Du Committed by Arnaldo Carvalho de Melo
Browse files

perf ftrace: Add option '-F/--funcs' to list available functions 



This adds an option '-F/--funcs' to list all available functions to
trace, which is read from tracing file 'available_filter_functions'.

  $ sudo ./perf ftrace -F | head
  trace_initcall_finish_cb
  initcall_blacklisted
  do_one_initcall
  do_one_initcall
  trace_initcall_start_cb
  run_init_process
  try_to_run_init_process
  match_dev_by_label
  match_dev_by_uuid
  rootfs_init_fs_context
  $

Committer notes:

This is the same command line option and for the same purpose as in
'perf probe'.

Signed-off-by: default avatarChangbin Du <changbin.du@gmail.com>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: default avatarNamhyung 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/20200808023141.14227-3-changbin.du@gmail.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent eb6d31ae

tools/perf/Documentation/perf-ftrace.txt

+4 −0
Original line number Diff line number Diff line
@@ -31,6 +31,10 @@ OPTIONS 
--verbose=::

        Verbosity level.



-F::

--funcs::

        List all available functions to trace.



-p::

--pid=::

	Trace on existing process id (comma separated list).

tools/perf/builtin-ftrace.c

+46 −0
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ struct perf_ftrace { 
	struct evlist		*evlist;

	struct target		target;

	const char		*tracer;

	bool			list_avail_functions;

	struct list_head	filters;

	struct list_head	notrace;

	struct list_head	graph_funcs;
@@ -128,6 +129,46 @@ static int append_tracing_file(const char *name, const char *val) 
	return __write_tracing_file(name, val, true);

}



static int read_tracing_file_to_stdout(const char *name)

{

	char buf[4096];

	char *file;

	int fd;

	int ret = -1;



	file = get_tracing_file(name);

	if (!file) {

		pr_debug("cannot get tracing file: %s\n", name);

		return -1;

	}



	fd = open(file, O_RDONLY);

	if (fd < 0) {

		pr_debug("cannot open tracing file: %s: %s\n",

			 name, str_error_r(errno, buf, sizeof(buf)));

		goto out;

	}



	/* read contents to stdout */

	while (true) {

		int n = read(fd, buf, sizeof(buf));

		if (n == 0)

			break;

		else if (n < 0)

			goto out_close;



		if (fwrite(buf, n, 1, stdout) != 1)

			goto out_close;

	}

	ret = 0;



out_close:

	close(fd);

out:

	put_tracing_file(file);

	return ret;

}



static int reset_tracing_cpu(void);

static void reset_tracing_filters(void);
@@ -302,6 +343,9 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv) 
	signal(SIGCHLD, sig_handler);

	signal(SIGPIPE, sig_handler);



	if (ftrace->list_avail_functions)

		return read_tracing_file_to_stdout("available_filter_functions");



	if (reset_tracing_files(ftrace) < 0) {

		pr_err("failed to reset ftrace\n");

		goto out;
@@ -487,6 +531,8 @@ int cmd_ftrace(int argc, const char **argv) 
	const struct option ftrace_options[] = {

	OPT_STRING('t', "tracer", &ftrace.tracer, "tracer",

		   "tracer to use: function_graph(default) or function"),

	OPT_BOOLEAN('F', "funcs", &ftrace.list_avail_functions,

		    "Show available functions to filter"),

	OPT_STRING('p', "pid", &ftrace.target.pid, "pid",

		   "trace on existing process id"),

	OPT_INCR('v', "verbose", &verbose,

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