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Commit d01f4e8d authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
Browse files

perf ftrace: Introduce new 'ftrace' tool 



The 'perf ftrace' command is a simple wrapper of kernel's ftrace
functionality.  It only supports single thread tracing currently and
just reads trace_pipe in text and then write it to stdout.

Committer notes:

Testing it:

  # perf ftrace -f function_graph usleep 123456
  <SNIP>
  2)               |  SyS_nanosleep() {
  2)               |    _copy_from_user() {
  <SNIP>
  2)   0.900 us    |      }
  2)   1.354 us    |    }
  2)               |    hrtimer_nanosleep() {
  2)   0.062 us    |      __hrtimer_init();
  2)               |      do_nanosleep() {
  2)               |        hrtimer_start_range_ns() {
  <SNIP>
  2)   5.025 us    |        }
  2)               |        schedule() {
  2)   0.125 us    |          rcu_note_context_switch();
  2)   0.057 us    |          _raw_spin_lock();
  2)               |          deactivate_task() {
  2)   0.369 us    |            update_rq_clock.part.77();
  2)               |            dequeue_task_fair() {
  <SNIP>
  2) + 22.453 us   |            }
  2) + 23.736 us   |          }
  2)               |          pick_next_task_fair() {
  <SNIP>
  2) + 47.167 us   |          }
  2)               |          pick_next_task_idle() {
  <SNIP>
  2)   4.462 us    |          }
  ------------------------------------------
  2)  usleep-20387  =>    <idle>-0
  ------------------------------------------

  2)   0.806 us    |  switch_mm_irqs_off();
  ------------------------------------------
  2)    <idle>-0    =>  usleep-20387
  ------------------------------------------

  2)   0.151 us    |          finish_task_switch();
  2) @ 123597.2 us |        }
  2)   0.037 us    |        _cond_resched();
  2)               |        hrtimer_try_to_cancel() {
  2)   0.064 us    |          hrtimer_active();
  2)   0.353 us    |        }
  2) @ 123605.3 us |      }
  2) @ 123606.2 us |    }
  2) @ 123608.3 us |  } /* SyS_nanosleep */
  2)               |  __do_page_fault() {
 <SNIP>

Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jeremy Eder <jeder@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>,
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/n/tip-r1hgmsj4dxny8arn3o9mw512@git.kernel.org


[ Various foward port fixes, add man page ]
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent a7619aef

tools/perf/Build

+1 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ perf-y += builtin-annotate.o 
perf-y += builtin-config.o

perf-y += builtin-diff.o

perf-y += builtin-evlist.o

perf-y += builtin-ftrace.o

perf-y += builtin-help.o

perf-y += builtin-sched.o

perf-y += builtin-buildid-list.o

tools/perf/Documentation/perf-ftrace.txt

0 → 100644
+36 −0
Original line number Diff line number Diff line 
perf-ftrace(1)

=============



NAME

----

perf-ftrace - simple wrapper for kernel's ftrace functionality





SYNOPSIS

--------

[verse]

'perf ftrace' <command>



DESCRIPTION

-----------

The 'perf ftrace' command is a simple wrapper of kernel's ftrace

functionality.  It only supports single thread tracing currently and

just reads trace_pipe in text and then write it to stdout.



The following options apply to perf ftrace.



OPTIONS

-------



-t::

--tracer=::

	Tracer to use: function_graph or function.



-v::

--verbose=::

        Verbosity level.





SEE ALSO

--------

linkperf:perf-record[1], linkperf:perf-trace[1]

tools/perf/builtin-ftrace.c

0 → 100644
+242 −0
Original line number Diff line number Diff line 
/*

 * builtin-ftrace.c

 *

 * Copyright (c) 2013  LG Electronics,  Namhyung Kim <namhyung@kernel.org>

 *

 * Released under the GPL v2.

 */



#include "builtin.h"

#include "perf.h"



#include <unistd.h>

#include <signal.h>



#include "debug.h"

#include <subcmd/parse-options.h>

#include "evlist.h"

#include "target.h"

#include "thread_map.h"





#define DEFAULT_TRACER  "function_graph"



struct perf_ftrace {

	struct perf_evlist *evlist;

	struct target target;

	const char *tracer;

};



static bool done;



static void sig_handler(int sig __maybe_unused)

{

	done = true;

}



/*

 * perf_evlist__prepare_workload will send a SIGUSR1 if the fork fails, since

 * we asked by setting its exec_error to the function below,

 * ftrace__workload_exec_failed_signal.

 *

 * XXX We need to handle this more appropriately, emitting an error, etc.

 */

static void ftrace__workload_exec_failed_signal(int signo __maybe_unused,

						siginfo_t *info __maybe_unused,

						void *ucontext __maybe_unused)

{

	/* workload_exec_errno = info->si_value.sival_int; */

	done = true;

}



static int write_tracing_file(const char *name, const char *val)

{

	char *file;

	int fd, ret = -1;

	ssize_t size = strlen(val);



	file = get_tracing_file(name);

	if (!file) {

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

		return -1;

	}



	fd = open(file, O_WRONLY);

	if (fd < 0) {

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

		goto out;

	}



	if (write(fd, val, size) == size)

		ret = 0;

	else

		pr_debug("write '%s' to tracing/%s failed\n", val, name);



	close(fd);

out:

	put_tracing_file(file);

	return ret;

}



static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)

{

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

		return -1;



	if (write_tracing_file("current_tracer", "nop") < 0)

		return -1;



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

		return -1;



	return 0;

}



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

{

	char *trace_file;

	int trace_fd;

	char *trace_pid;

	char buf[4096];

	struct pollfd pollfd = {

		.events = POLLIN,

	};



	if (geteuid() != 0) {

		pr_err("ftrace only works for root!\n");

		return -1;

	}



	if (argc < 1)

		return -1;



	signal(SIGINT, sig_handler);

	signal(SIGUSR1, sig_handler);

	signal(SIGCHLD, sig_handler);



	reset_tracing_files(ftrace);



	/* reset ftrace buffer */

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

		goto out;



	if (perf_evlist__prepare_workload(ftrace->evlist, &ftrace->target,

					  argv, false, ftrace__workload_exec_failed_signal) < 0)

		goto out;



	if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {

		pr_err("failed to set current_tracer to %s\n", ftrace->tracer);

		goto out;

	}



	if (asprintf(&trace_pid, "%d", thread_map__pid(ftrace->evlist->threads, 0)) < 0) {

		pr_err("failed to allocate pid string\n");

		goto out;

	}



	if (write_tracing_file("set_ftrace_pid", trace_pid) < 0) {

		pr_err("failed to set pid: %s\n", trace_pid);

		goto out_free_pid;

	}



	trace_file = get_tracing_file("trace_pipe");

	if (!trace_file) {

		pr_err("failed to open trace_pipe\n");

		goto out_free_pid;

	}



	trace_fd = open(trace_file, O_RDONLY);



	put_tracing_file(trace_file);



	if (trace_fd < 0) {

		pr_err("failed to open trace_pipe\n");

		goto out_free_pid;

	}



	fcntl(trace_fd, F_SETFL, O_NONBLOCK);

	pollfd.fd = trace_fd;



	if (write_tracing_file("tracing_on", "1") < 0) {

		pr_err("can't enable tracing\n");

		goto out_close_fd;

	}



	perf_evlist__start_workload(ftrace->evlist);



	while (!done) {

		if (poll(&pollfd, 1, -1) < 0)

			break;



		if (pollfd.revents & POLLIN) {

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

			if (n < 0)

				break;

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

				break;

		}

	}



	write_tracing_file("tracing_on", "0");



	/* read remaining buffer contents */

	while (true) {

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

		if (n <= 0)

			break;

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

			break;

	}



out_close_fd:

	close(trace_fd);

out_free_pid:

	free(trace_pid);

out:

	reset_tracing_files(ftrace);



	return done ? 0 : -1;

}



int cmd_ftrace(int argc, const char **argv, const char *prefix __maybe_unused)

{

	int ret;

	struct perf_ftrace ftrace = {

		.target = { .uid = UINT_MAX, },

	};

	const char * const ftrace_usage[] = {

		"perf ftrace [<options>] <command>",

		"perf ftrace [<options>] -- <command> [<options>]",

		NULL

	};

	const struct option ftrace_options[] = {

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

		   "tracer to use: function_graph or function"),

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

		 "be more verbose"),

	OPT_END()

	};



	argc = parse_options(argc, argv, ftrace_options, ftrace_usage,

			    PARSE_OPT_STOP_AT_NON_OPTION);

	if (!argc)

		usage_with_options(ftrace_usage, ftrace_options);



	ftrace.evlist = perf_evlist__new();

	if (ftrace.evlist == NULL)

		return -ENOMEM;



	ret = perf_evlist__create_maps(ftrace.evlist, &ftrace.target);

	if (ret < 0)

		goto out_delete_evlist;



	if (ftrace.tracer == NULL)

		ftrace.tracer = DEFAULT_TRACER;



	ret = __cmd_ftrace(&ftrace, argc, argv);



out_delete_evlist:

	perf_evlist__delete(ftrace.evlist);



	return ret;

}

tools/perf/builtin.h

+1 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ int cmd_trace(int argc, const char **argv, const char *prefix); 
int cmd_inject(int argc, const char **argv, const char *prefix);

int cmd_mem(int argc, const char **argv, const char *prefix);

int cmd_data(int argc, const char **argv, const char *prefix);

int cmd_ftrace(int argc, const char **argv, const char *prefix);



int find_scripts(char **scripts_array, char **scripts_path_array);

#endif

tools/perf/command-list.txt

+1 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ perf-data mainporcelain common 
perf-diff			mainporcelain common

perf-config			mainporcelain common

perf-evlist			mainporcelain common

perf-ftrace			mainporcelain common

perf-inject			mainporcelain common

perf-kallsyms			mainporcelain common

perf-kmem			mainporcelain common