4 * Copyright (c) 2013 LG Electronics, Namhyung Kim <namhyung@kernel.org>
6 * Released under the GPL v2.
19 #include <subcmd/parse-options.h>
20 #include <api/fs/tracing_path.h>
24 #include "thread_map.h"
25 #include "util/config.h"
28 #define DEFAULT_TRACER "function_graph"
31 struct perf_evlist *evlist;
38 static void sig_handler(int sig __maybe_unused)
44 * perf_evlist__prepare_workload will send a SIGUSR1 if the fork fails, since
45 * we asked by setting its exec_error to the function below,
46 * ftrace__workload_exec_failed_signal.
48 * XXX We need to handle this more appropriately, emitting an error, etc.
50 static void ftrace__workload_exec_failed_signal(int signo __maybe_unused,
51 siginfo_t *info __maybe_unused,
52 void *ucontext __maybe_unused)
54 /* workload_exec_errno = info->si_value.sival_int; */
58 static int __write_tracing_file(const char *name, const char *val, bool append)
62 ssize_t size = strlen(val);
65 file = get_tracing_file(name);
67 pr_debug("cannot get tracing file: %s\n", name);
76 fd = open(file, flags);
78 pr_debug("cannot open tracing file: %s\n", name);
82 if (write(fd, val, size) == size)
85 pr_debug("write '%s' to tracing/%s failed\n", val, name);
89 put_tracing_file(file);
93 static int write_tracing_file(const char *name, const char *val)
95 return __write_tracing_file(name, val, false);
98 static int append_tracing_file(const char *name, const char *val)
100 return __write_tracing_file(name, val, true);
103 static int reset_tracing_cpu(void);
105 static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
107 if (write_tracing_file("tracing_on", "0") < 0)
110 if (write_tracing_file("current_tracer", "nop") < 0)
113 if (write_tracing_file("set_ftrace_pid", " ") < 0)
116 if (reset_tracing_cpu() < 0)
122 static int set_tracing_pid(struct perf_ftrace *ftrace)
127 if (target__has_cpu(&ftrace->target))
130 for (i = 0; i < thread_map__nr(ftrace->evlist->threads); i++) {
131 scnprintf(buf, sizeof(buf), "%d",
132 ftrace->evlist->threads->map[i]);
133 if (append_tracing_file("set_ftrace_pid", buf) < 0)
139 static int set_tracing_cpumask(struct cpu_map *cpumap)
146 last_cpu = cpu_map__cpu(cpumap, cpumap->nr - 1);
147 mask_size = (last_cpu + 3) / 4 + 1;
148 mask_size += last_cpu / 32; /* ',' is needed for every 32th cpus */
150 cpumask = malloc(mask_size);
151 if (cpumask == NULL) {
152 pr_debug("failed to allocate cpu mask\n");
156 cpu_map__snprint_mask(cpumap, cpumask, mask_size);
158 ret = write_tracing_file("tracing_cpumask", cpumask);
164 static int set_tracing_cpu(struct perf_ftrace *ftrace)
166 struct cpu_map *cpumap = ftrace->evlist->cpus;
168 if (!target__has_cpu(&ftrace->target))
171 return set_tracing_cpumask(cpumap);
174 static int reset_tracing_cpu(void)
176 struct cpu_map *cpumap = cpu_map__new(NULL);
179 ret = set_tracing_cpumask(cpumap);
180 cpu_map__put(cpumap);
184 static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
189 struct pollfd pollfd = {
193 if (geteuid() != 0) {
194 pr_err("ftrace only works for root!\n");
198 signal(SIGINT, sig_handler);
199 signal(SIGUSR1, sig_handler);
200 signal(SIGCHLD, sig_handler);
201 signal(SIGPIPE, sig_handler);
203 if (reset_tracing_files(ftrace) < 0)
206 /* reset ftrace buffer */
207 if (write_tracing_file("trace", "0") < 0)
210 if (argc && perf_evlist__prepare_workload(ftrace->evlist,
211 &ftrace->target, argv, false,
212 ftrace__workload_exec_failed_signal) < 0) {
216 if (set_tracing_pid(ftrace) < 0) {
217 pr_err("failed to set ftrace pid\n");
221 if (set_tracing_cpu(ftrace) < 0) {
222 pr_err("failed to set tracing cpumask\n");
226 if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {
227 pr_err("failed to set current_tracer to %s\n", ftrace->tracer);
231 trace_file = get_tracing_file("trace_pipe");
233 pr_err("failed to open trace_pipe\n");
237 trace_fd = open(trace_file, O_RDONLY);
239 put_tracing_file(trace_file);
242 pr_err("failed to open trace_pipe\n");
246 fcntl(trace_fd, F_SETFL, O_NONBLOCK);
247 pollfd.fd = trace_fd;
249 if (write_tracing_file("tracing_on", "1") < 0) {
250 pr_err("can't enable tracing\n");
256 perf_evlist__start_workload(ftrace->evlist);
259 if (poll(&pollfd, 1, -1) < 0)
262 if (pollfd.revents & POLLIN) {
263 int n = read(trace_fd, buf, sizeof(buf));
266 if (fwrite(buf, n, 1, stdout) != 1)
271 write_tracing_file("tracing_on", "0");
273 /* read remaining buffer contents */
275 int n = read(trace_fd, buf, sizeof(buf));
278 if (fwrite(buf, n, 1, stdout) != 1)
285 reset_tracing_files(ftrace);
287 return done ? 0 : -1;
290 static int perf_ftrace_config(const char *var, const char *value, void *cb)
292 struct perf_ftrace *ftrace = cb;
294 if (prefixcmp(var, "ftrace."))
297 if (strcmp(var, "ftrace.tracer"))
300 if (!strcmp(value, "function_graph") ||
301 !strcmp(value, "function")) {
302 ftrace->tracer = value;
306 pr_err("Please select \"function_graph\" (default) or \"function\"\n");
310 int cmd_ftrace(int argc, const char **argv)
313 struct perf_ftrace ftrace = {
314 .tracer = DEFAULT_TRACER,
315 .target = { .uid = UINT_MAX, },
317 const char * const ftrace_usage[] = {
318 "perf ftrace [<options>] [<command>]",
319 "perf ftrace [<options>] -- <command> [<options>]",
322 const struct option ftrace_options[] = {
323 OPT_STRING('t', "tracer", &ftrace.tracer, "tracer",
324 "tracer to use: function_graph(default) or function"),
325 OPT_STRING('p', "pid", &ftrace.target.pid, "pid",
326 "trace on existing process id"),
327 OPT_INCR('v', "verbose", &verbose,
329 OPT_BOOLEAN('a', "all-cpus", &ftrace.target.system_wide,
330 "system-wide collection from all CPUs"),
331 OPT_STRING('C', "cpu", &ftrace.target.cpu_list, "cpu",
332 "list of cpus to monitor"),
336 ret = perf_config(perf_ftrace_config, &ftrace);
340 argc = parse_options(argc, argv, ftrace_options, ftrace_usage,
341 PARSE_OPT_STOP_AT_NON_OPTION);
342 if (!argc && target__none(&ftrace.target))
343 usage_with_options(ftrace_usage, ftrace_options);
345 ret = target__validate(&ftrace.target);
349 target__strerror(&ftrace.target, ret, errbuf, 512);
350 pr_err("%s\n", errbuf);
354 ftrace.evlist = perf_evlist__new();
355 if (ftrace.evlist == NULL)
358 ret = perf_evlist__create_maps(ftrace.evlist, &ftrace.target);
360 goto out_delete_evlist;
362 ret = __cmd_ftrace(&ftrace, argc, argv);
365 perf_evlist__delete(ftrace.evlist);