Commit 2ae05fe0 authored by Changbin Du's avatar Changbin Du Committed by Arnaldo Carvalho de Melo
Browse files

perf: ftrace: Add filter support for option -F/--funcs 



Same as 'perf probe -F', this patch adds filter support for the ftrace
subcommand option '-F, --funcs <[FILTER]>'.

Here is an example that only lists functions which start with 'vfs_':

  $ sudo perf ftrace -F vfs_*
  vfs_fadvise
  vfs_fallocate
  vfs_truncate
  vfs_open
  vfs_setpos
  vfs_llseek
  vfs_readf
  vfs_writef
  ...

Suggested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: default avatarChangbin Du <changbin.du@gmail.com>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200904152357.6053-1-changbin.du@gmail.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent ee7fe31e

tools/perf/Documentation/perf-ftrace.txt

+2 −1
Original line number Diff line number Diff line
@@ -33,7 +33,8 @@ OPTIONS 


-F::

--funcs::

        List all available functions to trace.

        List available functions to trace. It accepts a pattern to

        only list interested functions.



-p::

--pid=::

tools/perf/builtin-ftrace.c

+78 −6
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include "target.h"

#include "cpumap.h"

#include "thread_map.h"

#include "strfilter.h"

#include "util/cap.h"

#include "util/config.h"

#include "util/units.h"
@@ -36,7 +37,6 @@ 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;
@@ -181,6 +181,40 @@ static int read_tracing_file_to_stdout(const char *name) 
	return ret;

}



static int read_tracing_file_by_line(const char *name,

				     void (*cb)(char *str, void *arg),

				     void *cb_arg)

{

	char *line = NULL;

	size_t len = 0;

	char *file;

	FILE *fp;



	file = get_tracing_file(name);

	if (!file) {

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

		return -1;

	}



	fp = fopen(file, "r");

	if (fp == NULL) {

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

		put_tracing_file(file);

		return -1;

	}



	while (getline(&line, &len, fp) != -1) {

		cb(line, cb_arg);

	}



	if (line)

		free(line);



	fclose(fp);

	put_tracing_file(file);

	return 0;

}



static int write_tracing_file_int(const char *name, int value)

{

	char buf[16];
@@ -557,9 +591,6 @@ 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;
@@ -683,6 +714,46 @@ static int perf_ftrace_config(const char *var, const char *value, void *cb) 
	return -1;

}



static void list_function_cb(char *str, void *arg)

{

	struct strfilter *filter = (struct strfilter *)arg;



	if (strfilter__compare(filter, str))

		printf("%s", str);

}



static int opt_list_avail_functions(const struct option *opt __maybe_unused,

				    const char *str, int unset)

{

	struct strfilter *filter;

	const char *err = NULL;

	int ret;



	if (unset || !str)

		return -1;



	filter = strfilter__new(str, &err);

	if (!filter)

		return err ? -EINVAL : -ENOMEM;



	ret = strfilter__or(filter, str, &err);

	if (ret == -EINVAL) {

		pr_err("Filter parse error at %td.\n", err - str + 1);

		pr_err("Source: \"%s\"\n", str);

		pr_err("         %*c\n", (int)(err - str + 1), '^');

		strfilter__delete(filter);

		return ret;

	}



	ret = read_tracing_file_by_line("available_filter_functions",

					list_function_cb, filter);

	strfilter__delete(filter);

	if (ret < 0)

		return ret;



	exit(0);

}



static int parse_filter_func(const struct option *opt, const char *str,

			     int unset __maybe_unused)

{
@@ -817,8 +888,9 @@ 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_CALLBACK_DEFAULT('F', "funcs", NULL, "[FILTER]",

			     "Show available functions to filter",

			     opt_list_avail_functions, "*"),

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

		   "Trace on existing process id"),

	/* TODO: Add short option -t after -t/--tracer can be removed. */