[mirror_ubuntu-artful-kernel.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 <unistd.h>
#include <signal.h>
#include <fcntl.h>

#include "debug.h"
#include <subcmd/parse-options.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);

	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;
	}

	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, 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_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
	12	#include <unistd.h>
	13	#include <signal.h>
a9af6be5	14	#include <fcntl.h>
d01f4e8d NK	15
	16	#include "debug.h"
	17	#include <subcmd/parse-options.h>
	18	#include "evlist.h"
	19	#include "target.h"
dc231032	20	#include "cpumap.h"
d01f4e8d	21	#include "thread_map.h"
b05d1093	22	#include "util/config.h"
d01f4e8d NK	23
	24
	25	#define DEFAULT_TRACER "function_graph"
	26
	27	struct perf_ftrace {
	28	struct perf_evlist *evlist;
	29	struct target target;
	30	const char *tracer;
	31	};
	32
	33	static bool done;
	34
	35	static void sig_handler(int sig __maybe_unused)
	36	{
	37	done = true;
	38	}
	39
	40	/*
	41	* perf_evlist__prepare_workload will send a SIGUSR1 if the fork fails, since
	42	* we asked by setting its exec_error to the function below,
	43	* ftrace__workload_exec_failed_signal.
	44	*
	45	* XXX We need to handle this more appropriately, emitting an error, etc.
	46	*/
	47	static void ftrace__workload_exec_failed_signal(int signo __maybe_unused,
	48	siginfo_t *info __maybe_unused,
	49	void *ucontext __maybe_unused)
	50	{
	51	/* workload_exec_errno = info->si_value.sival_int; */
	52	done = true;
	53	}
	54
a9af6be5	55	static int __write_tracing_file(const char name, const char val, bool append)
d01f4e8d NK	56	{
	57	char *file;
	58	int fd, ret = -1;
	59	ssize_t size = strlen(val);
a9af6be5	60	int flags = O_WRONLY;
d01f4e8d NK	61
	62	file = get_tracing_file(name);
	63	if (!file) {
	64	pr_debug("cannot get tracing file: %s\n", name);
	65	return -1;
	66	}
	67
a9af6be5 NK	68	if (append)
	69	flags \|= O_APPEND;
	70	else
	71	flags \|= O_TRUNC;
	72
	73	fd = open(file, flags);
d01f4e8d NK	74	if (fd < 0) {
	75	pr_debug("cannot open tracing file: %s\n", name);
	76	goto out;
	77	}
	78
	79	if (write(fd, val, size) == size)
	80	ret = 0;
	81	else
	82	pr_debug("write '%s' to tracing/%s failed\n", val, name);
	83
	84	close(fd);
	85	out:
	86	put_tracing_file(file);
	87	return ret;
	88	}
	89
a9af6be5 NK	90	static int write_tracing_file(const char name, const char val)
	91	{
	92	return __write_tracing_file(name, val, false);
	93	}
	94
	95	static int append_tracing_file(const char name, const char val)
	96	{
	97	return __write_tracing_file(name, val, true);
	98	}
	99
dc231032 NK	100	static int reset_tracing_cpu(void);
dc231032 NK	101
d01f4e8d NK	102	static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
	103	{
	104	if (write_tracing_file("tracing_on", "0") < 0)
	105	return -1;
	106
	107	if (write_tracing_file("current_tracer", "nop") < 0)
	108	return -1;
	109
	110	if (write_tracing_file("set_ftrace_pid", " ") < 0)
	111	return -1;
	112
dc231032 NK	113	if (reset_tracing_cpu() < 0)
	114	return -1;
	115
d01f4e8d NK	116	return 0;
	117	}
	118
a9af6be5 NK	119	static int set_tracing_pid(struct perf_ftrace *ftrace)
	120	{
	121	int i;
	122	char buf[16];
	123
	124	if (target__has_cpu(&ftrace->target))
	125	return 0;
	126
	127	for (i = 0; i < thread_map__nr(ftrace->evlist->threads); i++) {
	128	scnprintf(buf, sizeof(buf), "%d",
	129	ftrace->evlist->threads->map[i]);
	130	if (append_tracing_file("set_ftrace_pid", buf) < 0)
	131	return -1;
	132	}
	133	return 0;
	134	}
	135
dc231032 NK	136	static int set_tracing_cpumask(struct cpu_map *cpumap)
	137	{
	138	char *cpumask;
	139	size_t mask_size;
	140	int ret;
	141	int last_cpu;
	142
	143	last_cpu = cpu_map__cpu(cpumap, cpumap->nr - 1);
	144	mask_size = (last_cpu + 3) / 4 + 1;
	145	mask_size += last_cpu / 32; /* ',' is needed for every 32th cpus */
	146
	147	cpumask = malloc(mask_size);
	148	if (cpumask == NULL) {
	149	pr_debug("failed to allocate cpu mask\n");
	150	return -1;
	151	}
	152
	153	cpu_map__snprint_mask(cpumap, cpumask, mask_size);
	154
	155	ret = write_tracing_file("tracing_cpumask", cpumask);
	156
	157	free(cpumask);
	158	return ret;
	159	}
	160
	161	static int set_tracing_cpu(struct perf_ftrace *ftrace)
	162	{
	163	struct cpu_map *cpumap = ftrace->evlist->cpus;
	164
	165	if (!target__has_cpu(&ftrace->target))
	166	return 0;
	167
	168	return set_tracing_cpumask(cpumap);
	169	}
	170
	171	static int reset_tracing_cpu(void)
	172	{
	173	struct cpu_map *cpumap = cpu_map__new(NULL);
	174	int ret;
	175
	176	ret = set_tracing_cpumask(cpumap);
	177	cpu_map__put(cpumap);
	178	return ret;
	179	}
	180
d01f4e8d NK	181	static int __cmd_ftrace(struct perf_ftrace ftrace, int argc, const char *argv)
	182	{
	183	char *trace_file;
	184	int trace_fd;
d01f4e8d NK	185	char buf[4096];
	186	struct pollfd pollfd = {
	187	.events = POLLIN,
	188	};
	189
	190	if (geteuid() != 0) {
	191	pr_err("ftrace only works for root!\n");
	192	return -1;
	193	}
	194
d01f4e8d NK	195	signal(SIGINT, sig_handler);
	196	signal(SIGUSR1, sig_handler);
	197	signal(SIGCHLD, sig_handler);
	198
a9af6be5 NK	199	if (reset_tracing_files(ftrace) < 0)
a9af6be5 NK	200	goto out;
d01f4e8d NK	201
	202	/* reset ftrace buffer */
	203	if (write_tracing_file("trace", "0") < 0)
	204	goto out;
	205
a9af6be5 NK	206	if (argc && perf_evlist__prepare_workload(ftrace->evlist,
	207	&ftrace->target, argv, false,
	208	ftrace__workload_exec_failed_signal) < 0) {
d01f4e8d NK	209	goto out;
	210	}
	211
a9af6be5 NK	212	if (set_tracing_pid(ftrace) < 0) {
	213	pr_err("failed to set ftrace pid\n");
	214	goto out_reset;
d01f4e8d NK	215	}
d01f4e8d NK	216
dc231032 NK	217	if (set_tracing_cpu(ftrace) < 0) {
	218	pr_err("failed to set tracing cpumask\n");
	219	goto out_reset;
	220	}
	221
a9af6be5 NK	222	if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {
	223	pr_err("failed to set current_tracer to %s\n", ftrace->tracer);
	224	goto out_reset;
d01f4e8d NK	225	}
	226
	227	trace_file = get_tracing_file("trace_pipe");
	228	if (!trace_file) {
	229	pr_err("failed to open trace_pipe\n");
a9af6be5	230	goto out_reset;
d01f4e8d NK	231	}
	232
	233	trace_fd = open(trace_file, O_RDONLY);
	234
	235	put_tracing_file(trace_file);
	236
	237	if (trace_fd < 0) {
	238	pr_err("failed to open trace_pipe\n");
a9af6be5	239	goto out_reset;
d01f4e8d NK	240	}
	241
	242	fcntl(trace_fd, F_SETFL, O_NONBLOCK);
	243	pollfd.fd = trace_fd;
	244
	245	if (write_tracing_file("tracing_on", "1") < 0) {
	246	pr_err("can't enable tracing\n");
	247	goto out_close_fd;
	248	}
	249
	250	perf_evlist__start_workload(ftrace->evlist);
	251
	252	while (!done) {
	253	if (poll(&pollfd, 1, -1) < 0)
	254	break;
	255
	256	if (pollfd.revents & POLLIN) {
	257	int n = read(trace_fd, buf, sizeof(buf));
	258	if (n < 0)
	259	break;
	260	if (fwrite(buf, n, 1, stdout) != 1)
	261	break;
	262	}
	263	}
	264
	265	write_tracing_file("tracing_on", "0");
	266
	267	/* read remaining buffer contents */
	268	while (true) {
	269	int n = read(trace_fd, buf, sizeof(buf));
	270	if (n <= 0)
	271	break;
	272	if (fwrite(buf, n, 1, stdout) != 1)
	273	break;
	274	}
	275
	276	out_close_fd:
	277	close(trace_fd);
a9af6be5	278	out_reset:
d01f4e8d	279	reset_tracing_files(ftrace);
a9af6be5	280	out:
d01f4e8d NK	281	return done ? 0 : -1;
	282	}
	283
b05d1093 TS	284	static int perf_ftrace_config(const char var, const char value, void *cb)
	285	{
	286	struct perf_ftrace *ftrace = cb;
	287
	288	if (prefixcmp(var, "ftrace."))
	289	return 0;
	290
	291	if (strcmp(var, "ftrace.tracer"))
	292	return -1;
	293
	294	if (!strcmp(value, "function_graph") \|\|
	295	!strcmp(value, "function")) {
	296	ftrace->tracer = value;
	297	return 0;
	298	}
	299
	300	pr_err("Please select \"function_graph\" (default) or \"function\"\n");
	301	return -1;
	302	}
	303
d01f4e8d NK	304	int cmd_ftrace(int argc, const char *argv, const char prefix __maybe_unused)
	305	{
	306	int ret;
	307	struct perf_ftrace ftrace = {
bf062bd2	308	.tracer = DEFAULT_TRACER,
d01f4e8d NK	309	.target = { .uid = UINT_MAX, },
	310	};
	311	const char * const ftrace_usage[] = {
a9af6be5	312	"perf ftrace [<options>] [<command>]",
d01f4e8d NK	313	"perf ftrace [<options>] -- <command> [<options>]",
	314	NULL
	315	};
	316	const struct option ftrace_options[] = {
	317	OPT_STRING('t', "tracer", &ftrace.tracer, "tracer",
ec347870	318	"tracer to use: function_graph(default) or function"),
a9af6be5 NK	319	OPT_STRING('p', "pid", &ftrace.target.pid, "pid",
a9af6be5 NK	320	"trace on existing process id"),
d01f4e8d NK	321	OPT_INCR('v', "verbose", &verbose,
d01f4e8d NK	322	"be more verbose"),
dc231032 NK	323	OPT_BOOLEAN('a', "all-cpus", &ftrace.target.system_wide,
	324	"system-wide collection from all CPUs"),
	325	OPT_STRING('C', "cpu", &ftrace.target.cpu_list, "cpu",
	326	"list of cpus to monitor"),
d01f4e8d NK	327	OPT_END()
	328	};
	329
b05d1093 TS	330	ret = perf_config(perf_ftrace_config, &ftrace);
	331	if (ret < 0)
	332	return -1;
	333
d01f4e8d NK	334	argc = parse_options(argc, argv, ftrace_options, ftrace_usage,
d01f4e8d NK	335	PARSE_OPT_STOP_AT_NON_OPTION);
a9af6be5	336	if (!argc && target__none(&ftrace.target))
d01f4e8d NK	337	usage_with_options(ftrace_usage, ftrace_options);
d01f4e8d NK	338
a9af6be5 NK	339	ret = target__validate(&ftrace.target);
	340	if (ret) {
	341	char errbuf[512];
	342
	343	target__strerror(&ftrace.target, ret, errbuf, 512);
	344	pr_err("%s\n", errbuf);
	345	return -EINVAL;
	346	}
	347
d01f4e8d NK	348	ftrace.evlist = perf_evlist__new();
	349	if (ftrace.evlist == NULL)
	350	return -ENOMEM;
	351
	352	ret = perf_evlist__create_maps(ftrace.evlist, &ftrace.target);
	353	if (ret < 0)
	354	goto out_delete_evlist;
	355
d01f4e8d NK	356	ret = __cmd_ftrace(&ftrace, argc, argv);
	357
	358	out_delete_evlist:
	359	perf_evlist__delete(ftrace.evlist);
	360
	361	return ret;
	362	}