[linux-2.6-block.git] / tools / perf / 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;
	char errbuf[512];

	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: %s\n",
			 name, str_error_r(errno, errbuf, sizeof(errbuf)));
		goto out;
	}

	if (write(fd, val, size) == size)
		ret = 0;
	else
		pr_debug("write '%s' to tracing/%s failed: %s\n",
			 val, name, str_error_r(errno, errbuf, sizeof(errbuf)));

	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;
	}

	setup_pager();

	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;
	}

	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;
}
Commit	Line	Data
d01f4e8d NK	1	/*
	2	* builtin-ftrace.c
	3	*
	4	* Copyright (c) 2013 LG Electronics, Namhyung Kim <namhyung@kernel.org>
	5	*
	6	* Released under the GPL v2.
	7	*/
	8
	9	#include "builtin.h"
	10	#include "perf.h"
	11
a43783ae	12	#include <errno.h>
d01f4e8d NK	13	#include <unistd.h>
d01f4e8d NK	14	#include <signal.h>
a9af6be5	15	#include <fcntl.h>
4208735d	16	#include <poll.h>
d01f4e8d NK	17
	18	#include "debug.h"
	19	#include <subcmd/parse-options.h>
20a9ed28	20	#include <api/fs/tracing_path.h>
d01f4e8d NK	21	#include "evlist.h"
d01f4e8d NK	22	#include "target.h"
dc231032	23	#include "cpumap.h"
d01f4e8d	24	#include "thread_map.h"
b05d1093	25	#include "util/config.h"
d01f4e8d NK	26
	27
	28	#define DEFAULT_TRACER "function_graph"
	29
	30	struct perf_ftrace {
	31	struct perf_evlist *evlist;
	32	struct target target;
	33	const char *tracer;
	34	};
	35
	36	static bool done;
	37
	38	static void sig_handler(int sig __maybe_unused)
	39	{
	40	done = true;
	41	}
	42
	43	/*
	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.
	47	*
	48	* XXX We need to handle this more appropriately, emitting an error, etc.
	49	*/
	50	static void ftrace__workload_exec_failed_signal(int signo __maybe_unused,
	51	siginfo_t *info __maybe_unused,
	52	void *ucontext __maybe_unused)
	53	{
	54	/* workload_exec_errno = info->si_value.sival_int; */
	55	done = true;
	56	}
	57
a9af6be5	58	static int __write_tracing_file(const char name, const char val, bool append)
d01f4e8d NK	59	{
	60	char *file;
	61	int fd, ret = -1;
	62	ssize_t size = strlen(val);
a9af6be5	63	int flags = O_WRONLY;
e7bd9ba2	64	char errbuf[512];
d01f4e8d NK	65
	66	file = get_tracing_file(name);
	67	if (!file) {
	68	pr_debug("cannot get tracing file: %s\n", name);
	69	return -1;
	70	}
	71
a9af6be5 NK	72	if (append)
	73	flags \|= O_APPEND;
	74	else
	75	flags \|= O_TRUNC;
	76
	77	fd = open(file, flags);
d01f4e8d	78	if (fd < 0) {
e7bd9ba2 NK	79	pr_debug("cannot open tracing file: %s: %s\n",
e7bd9ba2 NK	80	name, str_error_r(errno, errbuf, sizeof(errbuf)));
d01f4e8d NK	81	goto out;
	82	}
	83
	84	if (write(fd, val, size) == size)
	85	ret = 0;
	86	else
e7bd9ba2 NK	87	pr_debug("write '%s' to tracing/%s failed: %s\n",
e7bd9ba2 NK	88	val, name, str_error_r(errno, errbuf, sizeof(errbuf)));
d01f4e8d NK	89
	90	close(fd);
	91	out:
	92	put_tracing_file(file);
	93	return ret;
	94	}
	95
a9af6be5 NK	96	static int write_tracing_file(const char name, const char val)
	97	{
	98	return __write_tracing_file(name, val, false);
	99	}
	100
	101	static int append_tracing_file(const char name, const char val)
	102	{
	103	return __write_tracing_file(name, val, true);
	104	}
	105
dc231032 NK	106	static int reset_tracing_cpu(void);
dc231032 NK	107
d01f4e8d NK	108	static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
	109	{
	110	if (write_tracing_file("tracing_on", "0") < 0)
	111	return -1;
	112
	113	if (write_tracing_file("current_tracer", "nop") < 0)
	114	return -1;
	115
	116	if (write_tracing_file("set_ftrace_pid", " ") < 0)
	117	return -1;
	118
dc231032 NK	119	if (reset_tracing_cpu() < 0)
	120	return -1;
	121
d01f4e8d NK	122	return 0;
	123	}
	124
a9af6be5 NK	125	static int set_tracing_pid(struct perf_ftrace *ftrace)
	126	{
	127	int i;
	128	char buf[16];
	129
	130	if (target__has_cpu(&ftrace->target))
	131	return 0;
	132
	133	for (i = 0; i < thread_map__nr(ftrace->evlist->threads); i++) {
	134	scnprintf(buf, sizeof(buf), "%d",
	135	ftrace->evlist->threads->map[i]);
	136	if (append_tracing_file("set_ftrace_pid", buf) < 0)
	137	return -1;
	138	}
	139	return 0;
	140	}
	141
dc231032 NK	142	static int set_tracing_cpumask(struct cpu_map *cpumap)
	143	{
	144	char *cpumask;
	145	size_t mask_size;
	146	int ret;
	147	int last_cpu;
	148
	149	last_cpu = cpu_map__cpu(cpumap, cpumap->nr - 1);
	150	mask_size = (last_cpu + 3) / 4 + 1;
	151	mask_size += last_cpu / 32; /* ',' is needed for every 32th cpus */
	152
	153	cpumask = malloc(mask_size);
	154	if (cpumask == NULL) {
	155	pr_debug("failed to allocate cpu mask\n");
	156	return -1;
	157	}
	158
	159	cpu_map__snprint_mask(cpumap, cpumask, mask_size);
	160
	161	ret = write_tracing_file("tracing_cpumask", cpumask);
	162
	163	free(cpumask);
	164	return ret;
	165	}
	166
	167	static int set_tracing_cpu(struct perf_ftrace *ftrace)
	168	{
	169	struct cpu_map *cpumap = ftrace->evlist->cpus;
	170
	171	if (!target__has_cpu(&ftrace->target))
	172	return 0;
	173
	174	return set_tracing_cpumask(cpumap);
	175	}
	176
	177	static int reset_tracing_cpu(void)
	178	{
	179	struct cpu_map *cpumap = cpu_map__new(NULL);
	180	int ret;
	181
	182	ret = set_tracing_cpumask(cpumap);
	183	cpu_map__put(cpumap);
	184	return ret;
	185	}
	186
d01f4e8d NK	187	static int __cmd_ftrace(struct perf_ftrace ftrace, int argc, const char *argv)
	188	{
	189	char *trace_file;
	190	int trace_fd;
d01f4e8d NK	191	char buf[4096];
	192	struct pollfd pollfd = {
	193	.events = POLLIN,
	194	};
	195
	196	if (geteuid() != 0) {
	197	pr_err("ftrace only works for root!\n");
	198	return -1;
	199	}
	200
d01f4e8d NK	201	signal(SIGINT, sig_handler);
	202	signal(SIGUSR1, sig_handler);
	203	signal(SIGCHLD, sig_handler);
58335964	204	signal(SIGPIPE, sig_handler);
d01f4e8d	205
a9af6be5 NK	206	if (reset_tracing_files(ftrace) < 0)
a9af6be5 NK	207	goto out;
d01f4e8d NK	208
	209	/* reset ftrace buffer */
	210	if (write_tracing_file("trace", "0") < 0)
	211	goto out;
	212
a9af6be5 NK	213	if (argc && perf_evlist__prepare_workload(ftrace->evlist,
	214	&ftrace->target, argv, false,
	215	ftrace__workload_exec_failed_signal) < 0) {
d01f4e8d NK	216	goto out;
	217	}
	218
a9af6be5 NK	219	if (set_tracing_pid(ftrace) < 0) {
	220	pr_err("failed to set ftrace pid\n");
	221	goto out_reset;
d01f4e8d NK	222	}
d01f4e8d NK	223
dc231032 NK	224	if (set_tracing_cpu(ftrace) < 0) {
	225	pr_err("failed to set tracing cpumask\n");
	226	goto out_reset;
	227	}
	228
a9af6be5 NK	229	if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {
	230	pr_err("failed to set current_tracer to %s\n", ftrace->tracer);
	231	goto out_reset;
d01f4e8d NK	232	}
d01f4e8d NK	233
29681bc5 NK	234	setup_pager();
29681bc5 NK	235
d01f4e8d NK	236	trace_file = get_tracing_file("trace_pipe");
	237	if (!trace_file) {
	238	pr_err("failed to open trace_pipe\n");
a9af6be5	239	goto out_reset;
d01f4e8d NK	240	}
	241
	242	trace_fd = open(trace_file, O_RDONLY);
	243
	244	put_tracing_file(trace_file);
	245
	246	if (trace_fd < 0) {
	247	pr_err("failed to open trace_pipe\n");
a9af6be5	248	goto out_reset;
d01f4e8d NK	249	}
	250
	251	fcntl(trace_fd, F_SETFL, O_NONBLOCK);
	252	pollfd.fd = trace_fd;
	253
	254	if (write_tracing_file("tracing_on", "1") < 0) {
	255	pr_err("can't enable tracing\n");
	256	goto out_close_fd;
	257	}
	258
	259	perf_evlist__start_workload(ftrace->evlist);
	260
	261	while (!done) {
	262	if (poll(&pollfd, 1, -1) < 0)
	263	break;
	264
	265	if (pollfd.revents & POLLIN) {
	266	int n = read(trace_fd, buf, sizeof(buf));
	267	if (n < 0)
	268	break;
	269	if (fwrite(buf, n, 1, stdout) != 1)
	270	break;
	271	}
	272	}
	273
	274	write_tracing_file("tracing_on", "0");
	275
	276	/* read remaining buffer contents */
	277	while (true) {
	278	int n = read(trace_fd, buf, sizeof(buf));
	279	if (n <= 0)
	280	break;
	281	if (fwrite(buf, n, 1, stdout) != 1)
	282	break;
	283	}
	284
	285	out_close_fd:
	286	close(trace_fd);
a9af6be5	287	out_reset:
d01f4e8d	288	reset_tracing_files(ftrace);
a9af6be5	289	out:
d01f4e8d NK	290	return done ? 0 : -1;
	291	}
	292
b05d1093 TS	293	static int perf_ftrace_config(const char var, const char value, void *cb)
	294	{
	295	struct perf_ftrace *ftrace = cb;
	296
	297	if (prefixcmp(var, "ftrace."))
	298	return 0;
	299
	300	if (strcmp(var, "ftrace.tracer"))
	301	return -1;
	302
	303	if (!strcmp(value, "function_graph") \|\|
	304	!strcmp(value, "function")) {
	305	ftrace->tracer = value;
	306	return 0;
	307	}
	308
	309	pr_err("Please select \"function_graph\" (default) or \"function\"\n");
	310	return -1;
	311	}
	312
b0ad8ea6	313	int cmd_ftrace(int argc, const char **argv)
d01f4e8d NK	314	{
	315	int ret;
	316	struct perf_ftrace ftrace = {
bf062bd2	317	.tracer = DEFAULT_TRACER,
d01f4e8d NK	318	.target = { .uid = UINT_MAX, },
	319	};
	320	const char * const ftrace_usage[] = {
a9af6be5	321	"perf ftrace [<options>] [<command>]",
d01f4e8d NK	322	"perf ftrace [<options>] -- <command> [<options>]",
	323	NULL
	324	};
	325	const struct option ftrace_options[] = {
	326	OPT_STRING('t', "tracer", &ftrace.tracer, "tracer",
ec347870	327	"tracer to use: function_graph(default) or function"),
a9af6be5 NK	328	OPT_STRING('p', "pid", &ftrace.target.pid, "pid",
a9af6be5 NK	329	"trace on existing process id"),
d01f4e8d NK	330	OPT_INCR('v', "verbose", &verbose,
d01f4e8d NK	331	"be more verbose"),
dc231032 NK	332	OPT_BOOLEAN('a', "all-cpus", &ftrace.target.system_wide,
	333	"system-wide collection from all CPUs"),
	334	OPT_STRING('C', "cpu", &ftrace.target.cpu_list, "cpu",
	335	"list of cpus to monitor"),
d01f4e8d NK	336	OPT_END()
	337	};
	338
b05d1093 TS	339	ret = perf_config(perf_ftrace_config, &ftrace);
	340	if (ret < 0)
	341	return -1;
	342
d01f4e8d NK	343	argc = parse_options(argc, argv, ftrace_options, ftrace_usage,
d01f4e8d NK	344	PARSE_OPT_STOP_AT_NON_OPTION);
a9af6be5	345	if (!argc && target__none(&ftrace.target))
d01f4e8d NK	346	usage_with_options(ftrace_usage, ftrace_options);
d01f4e8d NK	347
a9af6be5 NK	348	ret = target__validate(&ftrace.target);
	349	if (ret) {
	350	char errbuf[512];
	351
	352	target__strerror(&ftrace.target, ret, errbuf, 512);
	353	pr_err("%s\n", errbuf);
	354	return -EINVAL;
	355	}
	356
d01f4e8d NK	357	ftrace.evlist = perf_evlist__new();
	358	if (ftrace.evlist == NULL)
	359	return -ENOMEM;
	360
	361	ret = perf_evlist__create_maps(ftrace.evlist, &ftrace.target);
	362	if (ret < 0)
	363	goto out_delete_evlist;
	364
d01f4e8d NK	365	ret = __cmd_ftrace(&ftrace, argc, argv);
	366
	367	out_delete_evlist:
	368	perf_evlist__delete(ftrace.evlist);
	369
	370	return ret;
	371	}