tools/perf/builtin-ftrace.c - arm/linux - Git at Google

 /*
  * 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;
 }
	/*
	* 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;
	}