tools/perf/util/parse-events.c

#include "../../../include/linux/hw_breakpoint.h"
#include "util.h"
#include "../perf.h"
#include "parse-options.h"
#include "parse-events.h"
#include "exec_cmd.h"
#include "string.h"
#include "cache.h"
#include "header.h"
#include "debugfs.h"

int				nr_counters;

struct perf_event_attr		attrs[MAX_COUNTERS];
char				*filters[MAX_COUNTERS];

struct event_symbol {
	u8		type;
	u64		config;
	const char	*symbol;
	const char	*alias;
};

enum event_result {
	EVT_FAILED,
	EVT_HANDLED,
	EVT_HANDLED_ALL
};

char debugfs_path[MAXPATHLEN];

#define CHW(x) .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_##x
#define CSW(x) .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_##x

static struct event_symbol event_symbols[] = {
  { CHW(CPU_CYCLES),		"cpu-cycles",		"cycles"	},
  { CHW(INSTRUCTIONS),		"instructions",		""		},
  { CHW(CACHE_REFERENCES),	"cache-references",	""		},
  { CHW(CACHE_MISSES),		"cache-misses",		""		},
  { CHW(BRANCH_INSTRUCTIONS),	"branch-instructions",	"branches"	},
  { CHW(BRANCH_MISSES),		"branch-misses",	""		},
  { CHW(BUS_CYCLES),		"bus-cycles",		""		},

  { CSW(CPU_CLOCK),		"cpu-clock",		""		},
  { CSW(TASK_CLOCK),		"task-clock",		""		},
  { CSW(PAGE_FAULTS),		"page-faults",		"faults"	},
  { CSW(PAGE_FAULTS_MIN),	"minor-faults",		""		},
  { CSW(PAGE_FAULTS_MAJ),	"major-faults",		""		},
  { CSW(CONTEXT_SWITCHES),	"context-switches",	"cs"		},
  { CSW(CPU_MIGRATIONS),	"cpu-migrations",	"migrations"	},
  { CSW(ALIGNMENT_FAULTS),	"alignment-faults",	""		},
  { CSW(EMULATION_FAULTS),	"emulation-faults",	""		},
};

#define __PERF_EVENT_FIELD(config, name) \
	((config & PERF_EVENT_##name##_MASK) >> PERF_EVENT_##name##_SHIFT)

#define PERF_EVENT_RAW(config)	__PERF_EVENT_FIELD(config, RAW)
#define PERF_EVENT_CONFIG(config)	__PERF_EVENT_FIELD(config, CONFIG)
#define PERF_EVENT_TYPE(config)	__PERF_EVENT_FIELD(config, TYPE)
#define PERF_EVENT_ID(config)		__PERF_EVENT_FIELD(config, EVENT)

static const char *hw_event_names[] = {
	"cycles",
	"instructions",
	"cache-references",
	"cache-misses",
	"branches",
	"branch-misses",
	"bus-cycles",
};

static const char *sw_event_names[] = {
	"cpu-clock-msecs",
	"task-clock-msecs",
	"page-faults",
	"context-switches",
	"CPU-migrations",
	"minor-faults",
	"major-faults",
	"alignment-faults",
	"emulation-faults",
};

#define MAX_ALIASES 8

static const char *hw_cache[][MAX_ALIASES] = {
 { "L1-dcache",	"l1-d",		"l1d",		"L1-data",		},
 { "L1-icache",	"l1-i",		"l1i",		"L1-instruction",	},
 { "LLC",	"L2"							},
 { "dTLB",	"d-tlb",	"Data-TLB",				},
 { "iTLB",	"i-tlb",	"Instruction-TLB",			},
 { "branch",	"branches",	"bpu",		"btb",		"bpc",	},
};

static const char *hw_cache_op[][MAX_ALIASES] = {
 { "load",	"loads",	"read",					},
 { "store",	"stores",	"write",				},
 { "prefetch",	"prefetches",	"speculative-read", "speculative-load",	},
};

static const char *hw_cache_result[][MAX_ALIASES] = {
 { "refs",	"Reference",	"ops",		"access",		},
 { "misses",	"miss",							},
};

#define C(x)		PERF_COUNT_HW_CACHE_##x
#define CACHE_READ	(1 << C(OP_READ))
#define CACHE_WRITE	(1 << C(OP_WRITE))
#define CACHE_PREFETCH	(1 << C(OP_PREFETCH))
#define COP(x)		(1 << x)

/*
 * cache operartion stat
 * L1I : Read and prefetch only
 * ITLB and BPU : Read-only
 */
static unsigned long hw_cache_stat[C(MAX)] = {
 [C(L1D)]	= (CACHE_READ | CACHE_WRITE | CACHE_PREFETCH),
 [C(L1I)]	= (CACHE_READ | CACHE_PREFETCH),
 [C(LL)]	= (CACHE_READ | CACHE_WRITE | CACHE_PREFETCH),
 [C(DTLB)]	= (CACHE_READ | CACHE_WRITE | CACHE_PREFETCH),
 [C(ITLB)]	= (CACHE_READ),
 [C(BPU)]	= (CACHE_READ),
};

#define for_each_subsystem(sys_dir, sys_dirent, sys_next)	       \
	while (!readdir_r(sys_dir, &sys_dirent, &sys_next) && sys_next)	       \
	if (sys_dirent.d_type == DT_DIR &&				       \
	   (strcmp(sys_dirent.d_name, ".")) &&				       \
	   (strcmp(sys_dirent.d_name, "..")))

static int tp_event_has_id(struct dirent *sys_dir, struct dirent *evt_dir)
{
	char evt_path[MAXPATHLEN];
	int fd;

	snprintf(evt_path, MAXPATHLEN, "%s/%s/%s/id", debugfs_path,
			sys_dir->d_name, evt_dir->d_name);
	fd = open(evt_path, O_RDONLY);
	if (fd < 0)
		return -EINVAL;
	close(fd);

	return 0;
}

#define for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next)	       \
	while (!readdir_r(evt_dir, &evt_dirent, &evt_next) && evt_next)        \
	if (evt_dirent.d_type == DT_DIR &&				       \
	   (strcmp(evt_dirent.d_name, ".")) &&				       \
	   (strcmp(evt_dirent.d_name, "..")) &&				       \
	   (!tp_event_has_id(&sys_dirent, &evt_dirent)))

#define MAX_EVENT_LENGTH 512


struct tracepoint_path *tracepoint_id_to_path(u64 config)
{
	struct tracepoint_path *path = NULL;
	DIR *sys_dir, *evt_dir;
	struct dirent *sys_next, *evt_next, sys_dirent, evt_dirent;
	char id_buf[4];
	int fd;
	u64 id;
	char evt_path[MAXPATHLEN];
	char dir_path[MAXPATHLEN];

	if (debugfs_valid_mountpoint(debugfs_path))
		return NULL;

	sys_dir = opendir(debugfs_path);
	if (!sys_dir)
		return NULL;

	for_each_subsystem(sys_dir, sys_dirent, sys_next) {

		snprintf(dir_path, MAXPATHLEN, "%s/%s", debugfs_path,
			 sys_dirent.d_name);
		evt_dir = opendir(dir_path);
		if (!evt_dir)
			continue;

		for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next) {

			snprintf(evt_path, MAXPATHLEN, "%s/%s/id", dir_path,
				 evt_dirent.d_name);
			fd = open(evt_path, O_RDONLY);
			if (fd < 0)
				continue;
			if (read(fd, id_buf, sizeof(id_buf)) < 0) {
				close(fd);
				continue;
			}
			close(fd);
			id = atoll(id_buf);
			if (id == config) {
				closedir(evt_dir);
				closedir(sys_dir);
				path = zalloc(sizeof(*path));
				path->system = malloc(MAX_EVENT_LENGTH);
				if (!path->system) {
					free(path);
					return NULL;
				}
				path->name = malloc(MAX_EVENT_LENGTH);
				if (!path->name) {
					free(path->system);
					free(path);
					return NULL;
				}
				strncpy(path->system, sys_dirent.d_name,
					MAX_EVENT_LENGTH);
				strncpy(path->name, evt_dirent.d_name,
					MAX_EVENT_LENGTH);
				return path;
			}
		}
		closedir(evt_dir);
	}

	closedir(sys_dir);
	return NULL;
}

#define TP_PATH_LEN (MAX_EVENT_LENGTH * 2 + 1)
static const char *tracepoint_id_to_name(u64 config)
{
	static char buf[TP_PATH_LEN];
	struct tracepoint_path *path;

	path = tracepoint_id_to_path(config);
	if (path) {
		snprintf(buf, TP_PATH_LEN, "%s:%s", path->system, path->name);
		free(path->name);
		free(path->system);
		free(path);
	} else
		snprintf(buf, TP_PATH_LEN, "%s:%s", "unknown", "unknown");

	return buf;
}

static int is_cache_op_valid(u8 cache_type, u8 cache_op)
{
	if (hw_cache_stat[cache_type] & COP(cache_op))
		return 1;	/* valid */
	else
		return 0;	/* invalid */
}

static char *event_cache_name(u8 cache_type, u8 cache_op, u8 cache_result)
{
	static char name[50];

	if (cache_result) {
		sprintf(name, "%s-%s-%s", hw_cache[cache_type][0],
			hw_cache_op[cache_op][0],
			hw_cache_result[cache_result][0]);
	} else {
		sprintf(name, "%s-%s", hw_cache[cache_type][0],
			hw_cache_op[cache_op][1]);
	}

	return name;
}

const char *event_name(int counter)
{
	u64 config = attrs[counter].config;
	int type = attrs[counter].type;

	return __event_name(type, config);
}

const char *__event_name(int type, u64 config)
{
	static char buf[32];

	if (type == PERF_TYPE_RAW) {
		sprintf(buf, "raw 0x%llx", config);
		return buf;
	}

	switch (type) {
	case PERF_TYPE_HARDWARE:
		if (config < PERF_COUNT_HW_MAX)
			return hw_event_names[config];
		return "unknown-hardware";

	case PERF_TYPE_HW_CACHE: {
		u8 cache_type, cache_op, cache_result;

		cache_type   = (config >>  0) & 0xff;
		if (cache_type > PERF_COUNT_HW_CACHE_MAX)
			return "unknown-ext-hardware-cache-type";

		cache_op     = (config >>  8) & 0xff;
		if (cache_op > PERF_COUNT_HW_CACHE_OP_MAX)
			return "unknown-ext-hardware-cache-op";

		cache_result = (config >> 16) & 0xff;
		if (cache_result > PERF_COUNT_HW_CACHE_RESULT_MAX)
			return "unknown-ext-hardware-cache-result";

		if (!is_cache_op_valid(cache_type, cache_op))
			return "invalid-cache";

		return event_cache_name(cache_type, cache_op, cache_result);
	}

	case PERF_TYPE_SOFTWARE:
		if (config < PERF_COUNT_SW_MAX)
			return sw_event_names[config];
		return "unknown-software";

	case PERF_TYPE_TRACEPOINT:
		return tracepoint_id_to_name(config);

	default:
		break;
	}

	return "unknown";
}

static int parse_aliases(const char **str, const char *names[][MAX_ALIASES], int size)
{
	int i, j;
	int n, longest = -1;

	for (i = 0; i < size; i++) {
		for (j = 0; j < MAX_ALIASES && names[i][j]; j++) {
			n = strlen(names[i][j]);
			if (n > longest && !strncasecmp(*str, names[i][j], n))
				longest = n;
		}
		if (longest > 0) {
			*str += longest;
			return i;
		}
	}

	return -1;
}

static enum event_result
parse_generic_hw_event(const char **str, struct perf_event_attr *attr)
{
	const char *s = *str;
	int cache_type = -1, cache_op = -1, cache_result = -1;

	cache_type = parse_aliases(&s, hw_cache, PERF_COUNT_HW_CACHE_MAX);
	/*
	 * No fallback - if we cannot get a clear cache type
	 * then bail out:
	 */
	if (cache_type == -1)
		return EVT_FAILED;

	while ((cache_op == -1 || cache_result == -1) && *s == '-') {
		++s;

		if (cache_op == -1) {
			cache_op = parse_aliases(&s, hw_cache_op,
						PERF_COUNT_HW_CACHE_OP_MAX);
			if (cache_op >= 0) {
				if (!is_cache_op_valid(cache_type, cache_op))
					return 0;
				continue;
			}
		}

		if (cache_result == -1) {
			cache_result = parse_aliases(&s, hw_cache_result,
						PERF_COUNT_HW_CACHE_RESULT_MAX);
			if (cache_result >= 0)
				continue;
		}

		/*
		 * Can't parse this as a cache op or result, so back up
		 * to the '-'.
		 */
		--s;
		break;
	}

	/*
	 * Fall back to reads:
	 */
	if (cache_op == -1)
		cache_op = PERF_COUNT_HW_CACHE_OP_READ;

	/*
	 * Fall back to accesses:
	 */
	if (cache_result == -1)
		cache_result = PERF_COUNT_HW_CACHE_RESULT_ACCESS;

	attr->config = cache_type | (cache_op << 8) | (cache_result << 16);
	attr->type = PERF_TYPE_HW_CACHE;

	*str = s;
	return EVT_HANDLED;
}

static enum event_result
parse_single_tracepoint_event(char *sys_name,
			      const char *evt_name,
			      unsigned int evt_length,
			      char *flags,
			      struct perf_event_attr *attr,
			      const char **strp)
{
	char evt_path[MAXPATHLEN];
	char id_buf[4];
	u64 id;
	int fd;

	if (flags) {
		if (!strncmp(flags, "record", strlen(flags))) {
			attr->sample_type |= PERF_SAMPLE_RAW;
			attr->sample_type |= PERF_SAMPLE_TIME;
			attr->sample_type |= PERF_SAMPLE_CPU;
		}
	}

	snprintf(evt_path, MAXPATHLEN, "%s/%s/%s/id", debugfs_path,
		 sys_name, evt_name);

	fd = open(evt_path, O_RDONLY);
	if (fd < 0)
		return EVT_FAILED;

	if (read(fd, id_buf, sizeof(id_buf)) < 0) {
		close(fd);
		return EVT_FAILED;
	}

	close(fd);
	id = atoll(id_buf);
	attr->config = id;
	attr->type = PERF_TYPE_TRACEPOINT;
	*strp = evt_name + evt_length;

	return EVT_HANDLED;
}

/* sys + ':' + event + ':' + flags*/
#define MAX_EVOPT_LEN	(MAX_EVENT_LENGTH * 2 + 2 + 128)
static enum event_result
parse_multiple_tracepoint_event(char *sys_name, const char *evt_exp,
				char *flags)
{
	char evt_path[MAXPATHLEN];
	struct dirent *evt_ent;
	DIR *evt_dir;

	snprintf(evt_path, MAXPATHLEN, "%s/%s", debugfs_path, sys_name);
	evt_dir = opendir(evt_path);

	if (!evt_dir) {
		perror("Can't open event dir");
		return EVT_FAILED;
	}

	while ((evt_ent = readdir(evt_dir))) {
		char event_opt[MAX_EVOPT_LEN + 1];
		int len;

		if (!strcmp(evt_ent->d_name, ".")
		    || !strcmp(evt_ent->d_name, "..")
		    || !strcmp(evt_ent->d_name, "enable")
		    || !strcmp(evt_ent->d_name, "filter"))
			continue;

		if (!strglobmatch(evt_ent->d_name, evt_exp))
			continue;

		len = snprintf(event_opt, MAX_EVOPT_LEN, "%s:%s%s%s", sys_name,
			       evt_ent->d_name, flags ? ":" : "",
			       flags ?: "");
		if (len < 0)
			return EVT_FAILED;

		if (parse_events(NULL, event_opt, 0))
			return EVT_FAILED;
	}

	return EVT_HANDLED_ALL;
}


static enum event_result parse_tracepoint_event(const char **strp,
				    struct perf_event_attr *attr)
{
	const char *evt_name;
	char *flags;
	char sys_name[MAX_EVENT_LENGTH];
	unsigned int sys_length, evt_length;

	if (debugfs_valid_mountpoint(debugfs_path))
		return 0;

	evt_name = strchr(*strp, ':');
	if (!evt_name)
		return EVT_FAILED;

	sys_length = evt_name - *strp;
	if (sys_length >= MAX_EVENT_LENGTH)
		return 0;

	strncpy(sys_name, *strp, sys_length);
	sys_name[sys_length] = '\0';
	evt_name = evt_name + 1;

	flags = strchr(evt_name, ':');
	if (flags) {
		/* split it out: */
		evt_name = strndup(evt_name, flags - evt_name);
		flags++;
	}

	evt_length = strlen(evt_name);
	if (evt_length >= MAX_EVENT_LENGTH)
		return EVT_FAILED;

	if (strpbrk(evt_name, "*?")) {
		*strp = evt_name + evt_length;
		return parse_multiple_tracepoint_event(sys_name, evt_name,
						       flags);
	} else
		return parse_single_tracepoint_event(sys_name, evt_name,
						     evt_length, flags,
						     attr, strp);
}

static enum event_result
parse_breakpoint_type(const char *type, const char **strp,
		      struct perf_event_attr *attr)
{
	int i;

	for (i = 0; i < 3; i++) {
		if (!type[i])
			break;

		switch (type[i]) {
		case 'r':
			attr->bp_type |= HW_BREAKPOINT_R;
			break;
		case 'w':
			attr->bp_type |= HW_BREAKPOINT_W;
			break;
		case 'x':
			attr->bp_type |= HW_BREAKPOINT_X;
			break;
		default:
			return EVT_FAILED;
		}
	}
	if (!attr->bp_type) /* Default */
		attr->bp_type = HW_BREAKPOINT_R | HW_BREAKPOINT_W;

	*strp = type + i;

	return EVT_HANDLED;
}

static enum event_result
parse_breakpoint_event(const char **strp, struct perf_event_attr *attr)
{
	const char *target;
	const char *type;
	char *endaddr;
	u64 addr;
	enum event_result err;

	target = strchr(*strp, ':');
	if (!target)
		return EVT_FAILED;

	if (strncmp(*strp, "mem", target - *strp) != 0)
		return EVT_FAILED;

	target++;

	addr = strtoull(target, &endaddr, 0);
	if (target == endaddr)
		return EVT_FAILED;

	attr->bp_addr = addr;
	*strp = endaddr;

	type = strchr(target, ':');

	/* If no type is defined, just rw as default */
	if (!type) {
		attr->bp_type = HW_BREAKPOINT_R | HW_BREAKPOINT_W;
	} else {
		err = parse_breakpoint_type(++type, strp, attr);
		if (err == EVT_FAILED)
			return EVT_FAILED;
	}

	/* We should find a nice way to override the access type */
	attr->bp_len = HW_BREAKPOINT_LEN_4;
	attr->type = PERF_TYPE_BREAKPOINT;

	return EVT_HANDLED;
}

static int check_events(const char *str, unsigned int i)
{
	int n;

	n = strlen(event_symbols[i].symbol);
	if (!strncmp(str, event_symbols[i].symbol, n))
		return n;

	n = strlen(event_symbols[i].alias);
	if (n)
		if (!strncmp(str, event_symbols[i].alias, n))
			return n;
	return 0;
}

static enum event_result
parse_symbolic_event(const char **strp, struct perf_event_attr *attr)
{
	const char *str = *strp;
	unsigned int i;
	int n;

	for (i = 0; i < ARRAY_SIZE(event_symbols); i++) {
		n = check_events(str, i);
		if (n > 0) {
			attr->type = event_symbols[i].type;
			attr->config = event_symbols[i].config;
			*strp = str + n;
			return EVT_HANDLED;
		}
	}
	return EVT_FAILED;
}

static enum event_result
parse_raw_event(const char **strp, struct perf_event_attr *attr)
{
	const char *str = *strp;
	u64 config;
	int n;

	if (*str != 'r')
		return EVT_FAILED;
	n = hex2u64(str + 1, &config);
	if (n > 0) {
		*strp = str + n + 1;
		attr->type = PERF_TYPE_RAW;
		attr->config = config;
		return EVT_HANDLED;
	}
	return EVT_FAILED;
}

static enum event_result
parse_numeric_event(const char **strp, struct perf_event_attr *attr)
{
	const char *str = *strp;
	char *endp;
	unsigned long type;
	u64 config;

	type = strtoul(str, &endp, 0);
	if (endp > str && type < PERF_TYPE_MAX && *endp == ':') {
		str = endp + 1;
		config = strtoul(str, &endp, 0);
		if (endp > str) {
			attr->type = type;
			attr->config = config;
			*strp = endp;
			return EVT_HANDLED;
		}
	}
	return EVT_FAILED;
}

static enum event_result
parse_event_modifier(const char **strp, struct perf_event_attr *attr)
{
	const char *str = *strp;
	int eu = 1, ek = 1, eh = 1;

	if (*str++ != ':')
		return 0;
	while (*str) {
		if (*str == 'u')
			eu = 0;
		else if (*str == 'k')
			ek = 0;
		else if (*str == 'h')
			eh = 0;
		else
			break;
		++str;
	}
	if (str >= *strp + 2) {
		*strp = str;
		attr->exclude_user   = eu;
		attr->exclude_kernel = ek;
		attr->exclude_hv     = eh;
		return 1;
	}
	return 0;
}

/*
 * Each event can have multiple symbolic names.
 * Symbolic names are (almost) exactly matched.
 */
static enum event_result
parse_event_symbols(const char **str, struct perf_event_attr *attr)
{
	enum event_result ret;

	ret = parse_tracepoint_event(str, attr);
	if (ret != EVT_FAILED)
		goto modifier;

	ret = parse_raw_event(str, attr);
	if (ret != EVT_FAILED)
		goto modifier;

	ret = parse_numeric_event(str, attr);
	if (ret != EVT_FAILED)
		goto modifier;

	ret = parse_symbolic_event(str, attr);
	if (ret != EVT_FAILED)
		goto modifier;

	ret = parse_generic_hw_event(str, attr);
	if (ret != EVT_FAILED)
		goto modifier;

	ret = parse_breakpoint_event(str, attr);
	if (ret != EVT_FAILED)
		goto modifier;

	fprintf(stderr, "invalid or unsupported event: '%s'\n", *str);
	fprintf(stderr, "Run 'perf list' for a list of valid events\n");
	return EVT_FAILED;

modifier:
	parse_event_modifier(str, attr);

	return ret;
}

static int store_event_type(const char *orgname)
{
	char filename[PATH_MAX], *c;
	FILE *file;
	int id, n;

	sprintf(filename, "%s/", debugfs_path);
	strncat(filename, orgname, strlen(orgname));
	strcat(filename, "/id");

	c = strchr(filename, ':');
	if (c)
		*c = '/';

	file = fopen(filename, "r");
	if (!file)
		return 0;
	n = fscanf(file, "%i", &id);
	fclose(file);
	if (n < 1) {
		pr_err("cannot store event ID\n");
		return -EINVAL;
	}
	return perf_header__push_event(id, orgname);
}

int parse_events(const struct option *opt __used, const char *str, int unset __used)
{
	struct perf_event_attr attr;
	enum event_result ret;

	if (strchr(str, ':'))
		if (store_event_type(str) < 0)
			return -1;

	for (;;) {
		if (nr_counters == MAX_COUNTERS)
			return -1;

		memset(&attr, 0, sizeof(attr));
		ret = parse_event_symbols(&str, &attr);
		if (ret == EVT_FAILED)
			return -1;

		if (!(*str == 0 || *str == ',' || isspace(*str)))
			return -1;

		if (ret != EVT_HANDLED_ALL) {
			attrs[nr_counters] = attr;
			nr_counters++;
		}

		if (*str == 0)
			break;
		if (*str == ',')
			++str;
		while (isspace(*str))
			++str;
	}

	return 0;
}

int parse_filter(const struct option *opt __used, const char *str,
		 int unset __used)
{
	int i = nr_counters - 1;
	int len = strlen(str);

	if (i < 0 || attrs[i].type != PERF_TYPE_TRACEPOINT) {
		fprintf(stderr,
			"-F option should follow a -e tracepoint option\n");
		return -1;
	}

	filters[i] = malloc(len + 1);
	if (!filters[i]) {
		fprintf(stderr, "not enough memory to hold filter string\n");
		return -1;
	}
	strcpy(filters[i], str);

	return 0;
}

static const char * const event_type_descriptors[] = {
	"Hardware event",
	"Software event",
	"Tracepoint event",
	"Hardware cache event",
	"Raw hardware event descriptor",
	"Hardware breakpoint",
};

/*
 * Print the events from <debugfs_mount_point>/tracing/events
 */

static void print_tracepoint_events(void)
{
	DIR *sys_dir, *evt_dir;
	struct dirent *sys_next, *evt_next, sys_dirent, evt_dirent;
	char evt_path[MAXPATHLEN];
	char dir_path[MAXPATHLEN];

	if (debugfs_valid_mountpoint(debugfs_path))
		return;

	sys_dir = opendir(debugfs_path);
	if (!sys_dir)
		return;

	for_each_subsystem(sys_dir, sys_dirent, sys_next) {

		snprintf(dir_path, MAXPATHLEN, "%s/%s", debugfs_path,
			 sys_dirent.d_name);
		evt_dir = opendir(dir_path);
		if (!evt_dir)
			continue;

		for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next) {
			snprintf(evt_path, MAXPATHLEN, "%s:%s",
				 sys_dirent.d_name, evt_dirent.d_name);
			printf("  %-42s [%s]\n", evt_path,
				event_type_descriptors[PERF_TYPE_TRACEPOINT]);
		}
		closedir(evt_dir);
	}
	closedir(sys_dir);
}

/*
 * Print the help text for the event symbols:
 */
void print_events(void)
{
	struct event_symbol *syms = event_symbols;
	unsigned int i, type, op, prev_type = -1;
	char name[40];

	printf("\n");
	printf("List of pre-defined events (to be used in -e):\n");

	for (i = 0; i < ARRAY_SIZE(event_symbols); i++, syms++) {
		type = syms->type;

		if (type != prev_type)
			printf("\n");

		if (strlen(syms->alias))
			sprintf(name, "%s OR %s", syms->symbol, syms->alias);
		else
			strcpy(name, syms->symbol);
		printf("  %-42s [%s]\n", name,
			event_type_descriptors[type]);

		prev_type = type;
	}

	printf("\n");
	for (type = 0; type < PERF_COUNT_HW_CACHE_MAX; type++) {
		for (op = 0; op < PERF_COUNT_HW_CACHE_OP_MAX; op++) {
			/* skip invalid cache type */
			if (!is_cache_op_valid(type, op))
				continue;

			for (i = 0; i < PERF_COUNT_HW_CACHE_RESULT_MAX; i++) {
				printf("  %-42s [%s]\n",
					event_cache_name(type, op, i),
					event_type_descriptors[PERF_TYPE_HW_CACHE]);
			}
		}
	}

	printf("\n");
	printf("  %-42s [%s]\n",
		"rNNN", event_type_descriptors[PERF_TYPE_RAW]);
	printf("\n");

	printf("  %-42s [%s]\n",
			"mem:<addr>[:access]",
			event_type_descriptors[PERF_TYPE_BREAKPOINT]);
	printf("\n");

	print_tracepoint_events();

	exit(129);
}