swh:1:snp:c2847dfd741eae21606027cf29250d1ebcd63fb4
Tip revision: 32c1431eea4881a6b17bd7c639315010aeefa452 authored by Linus Torvalds on 11 June 2017, 23:48:20 UTC
Linux 4.12-rc5
Linux 4.12-rc5
Tip revision: 32c1431
builtin-ftrace.c
/*
* 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 <errno.h>
#include <unistd.h>
#include <signal.h>
#include <fcntl.h>
#include <poll.h>
#include "debug.h"
#include <subcmd/parse-options.h>
#include <api/fs/tracing_path.h>
#include "evlist.h"
#include "target.h"
#include "cpumap.h"
#include "thread_map.h"
#include "util/config.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, bool append)
{
char *file;
int fd, ret = -1;
ssize_t size = strlen(val);
int flags = O_WRONLY;
file = get_tracing_file(name);
if (!file) {
pr_debug("cannot get tracing file: %s\n", name);
return -1;
}
if (append)
flags |= O_APPEND;
else
flags |= O_TRUNC;
fd = open(file, flags);
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 write_tracing_file(const char *name, const char *val)
{
return __write_tracing_file(name, val, false);
}
static int append_tracing_file(const char *name, const char *val)
{
return __write_tracing_file(name, val, true);
}
static int reset_tracing_cpu(void);
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;
if (reset_tracing_cpu() < 0)
return -1;
return 0;
}
static int set_tracing_pid(struct perf_ftrace *ftrace)
{
int i;
char buf[16];
if (target__has_cpu(&ftrace->target))
return 0;
for (i = 0; i < thread_map__nr(ftrace->evlist->threads); i++) {
scnprintf(buf, sizeof(buf), "%d",
ftrace->evlist->threads->map[i]);
if (append_tracing_file("set_ftrace_pid", buf) < 0)
return -1;
}
return 0;
}
static int set_tracing_cpumask(struct cpu_map *cpumap)
{
char *cpumask;
size_t mask_size;
int ret;
int last_cpu;
last_cpu = cpu_map__cpu(cpumap, cpumap->nr - 1);
mask_size = (last_cpu + 3) / 4 + 1;
mask_size += last_cpu / 32; /* ',' is needed for every 32th cpus */
cpumask = malloc(mask_size);
if (cpumask == NULL) {
pr_debug("failed to allocate cpu mask\n");
return -1;
}
cpu_map__snprint_mask(cpumap, cpumask, mask_size);
ret = write_tracing_file("tracing_cpumask", cpumask);
free(cpumask);
return ret;
}
static int set_tracing_cpu(struct perf_ftrace *ftrace)
{
struct cpu_map *cpumap = ftrace->evlist->cpus;
if (!target__has_cpu(&ftrace->target))
return 0;
return set_tracing_cpumask(cpumap);
}
static int reset_tracing_cpu(void)
{
struct cpu_map *cpumap = cpu_map__new(NULL);
int ret;
ret = set_tracing_cpumask(cpumap);
cpu_map__put(cpumap);
return ret;
}
static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
{
char *trace_file;
int trace_fd;
char buf[4096];
struct pollfd pollfd = {
.events = POLLIN,
};
if (geteuid() != 0) {
pr_err("ftrace only works for root!\n");
return -1;
}
signal(SIGINT, sig_handler);
signal(SIGUSR1, sig_handler);
signal(SIGCHLD, sig_handler);
signal(SIGPIPE, sig_handler);
if (reset_tracing_files(ftrace) < 0)
goto out;
/* reset ftrace buffer */
if (write_tracing_file("trace", "0") < 0)
goto out;
if (argc && perf_evlist__prepare_workload(ftrace->evlist,
&ftrace->target, argv, false,
ftrace__workload_exec_failed_signal) < 0) {
goto out;
}
if (set_tracing_pid(ftrace) < 0) {
pr_err("failed to set ftrace pid\n");
goto out_reset;
}
if (set_tracing_cpu(ftrace) < 0) {
pr_err("failed to set tracing cpumask\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;
}
trace_file = get_tracing_file("trace_pipe");
if (!trace_file) {
pr_err("failed to open trace_pipe\n");
goto out_reset;
}
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_reset;
}
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;
}
setup_pager();
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_reset:
reset_tracing_files(ftrace);
out:
return done ? 0 : -1;
}
static int perf_ftrace_config(const char *var, const char *value, void *cb)
{
struct perf_ftrace *ftrace = cb;
if (prefixcmp(var, "ftrace."))
return 0;
if (strcmp(var, "ftrace.tracer"))
return -1;
if (!strcmp(value, "function_graph") ||
!strcmp(value, "function")) {
ftrace->tracer = value;
return 0;
}
pr_err("Please select \"function_graph\" (default) or \"function\"\n");
return -1;
}
int cmd_ftrace(int argc, const char **argv)
{
int ret;
struct perf_ftrace ftrace = {
.tracer = DEFAULT_TRACER,
.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(default) or function"),
OPT_STRING('p', "pid", &ftrace.target.pid, "pid",
"trace on existing process id"),
OPT_INCR('v', "verbose", &verbose,
"be more verbose"),
OPT_BOOLEAN('a', "all-cpus", &ftrace.target.system_wide,
"system-wide collection from all CPUs"),
OPT_STRING('C', "cpu", &ftrace.target.cpu_list, "cpu",
"list of cpus to monitor"),
OPT_END()
};
ret = perf_config(perf_ftrace_config, &ftrace);
if (ret < 0)
return -1;
argc = parse_options(argc, argv, ftrace_options, ftrace_usage,
PARSE_OPT_STOP_AT_NON_OPTION);
if (!argc && target__none(&ftrace.target))
usage_with_options(ftrace_usage, ftrace_options);
ret = target__validate(&ftrace.target);
if (ret) {
char errbuf[512];
target__strerror(&ftrace.target, ret, errbuf, 512);
pr_err("%s\n", errbuf);
return -EINVAL;
}
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;
ret = __cmd_ftrace(&ftrace, argc, argv);
out_delete_evlist:
perf_evlist__delete(ftrace.evlist);
return ret;
}