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

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
......@@ -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
......
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]
/*
* 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;
}
......@@ -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
......@@ -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
......
......@@ -71,6 +71,7 @@ static struct cmd_struct commands[] = {
{ "inject", cmd_inject, 0 },
{ "mem", cmd_mem, 0 },
{ "data", cmd_data, 0 },
{ "ftrace", cmd_ftrace, 0 },
};
struct pager_config {
......
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