linux/tools/perf/builtin-ftrace.c

266 lines
5.4 KiB
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 <unistd.h>
#include <signal.h>
#include "debug.h"
#include <subcmd/parse-options.h>
#include "evlist.h"
#include "target.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)
{
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;
}
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, const char *prefix __maybe_unused)
{
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_INCR('v', "verbose", &verbose,
"be more verbose"),
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)
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;
ret = __cmd_ftrace(&ftrace, argc, argv);
out_delete_evlist:
perf_evlist__delete(ftrace.evlist);
return ret;
}