Merge tag 'perf-tools-for-v6.10-1-2024-05-21' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools

Pull perf tools updates from Arnaldo Carvalho de Melo:
 "General:

   - Integrate the shellcheck utility with the build of perf to allow
     catching shell problems early in areas such as 'perf test', 'perf
     trace' scrape scripts, etc

   - Add 'uretprobe' variant in the 'perf bench uprobe' tool

   - Add script to run instances of 'perf script' in parallel

   - Allow parsing tracepoint names that start with digits, such as
     9p/9p_client_req, etc. Make sure 'perf test' tests it even on
     systems where those tracepoints aren't available

   - Add Kan Liang to MAINTAINERS as a perf tools reviewer

   - Add support for using the 'capstone' disassembler library in
     various tools, such as 'perf script' and 'perf annotate'. This is
     an alternative for the use of the 'xed' and 'objdump' disassemblers

  Data-type profiling improvements:

   - Resolve types for a->b->c by backtracking the assignments until it
     finds DWARF info for one of those members

   - Support for global variables, keeping a cache to speed up lookups

   - Handle the 'call' instruction, dealing with effects on registers
     and handling its return when tracking register data types

   - Handle x86's segment based addressing like %gs:0x28, to support
     things like per CPU variables, the stack canary, etc

   - Data-type profiling got big speedups when using capstone for
     disassembling. The objdump outoput parsing method is left as a
     fallback when capstone fails or isn't available. There are patches
     posted for 6.11 that to use a LLVM disassembler

   - Support event group display in the TUI when annotating types with
     --data-type, for instance to show memory load and store events for
     the data type fields

   - Optimize the 'perf annotate' data structures, reducing memory usage

   - Add a initial 'perf test' for 'perf annotate', checking that a
     target symbol appears on the output, specifying objdump via the
     command line, etc

  Vendor Events:

   - Update Intel JSON files for Cascade Lake X, Emerald Rapids, Grand
     Ridge, Ice Lake X, Lunar Lake, Meteor Lake, Sapphire Rapids, Sierra
     Forest, Sky Lake X, Sky Lake and Snow Ridge X. Remove info metrics
     erroneously in TopdownL1

   - Add AMD's Zen 5 core and uncore events and metrics. Those come from
     the "Performance Monitor Counters for AMD Family 1Ah Model 00h- 0Fh
     Processors" document, with events that capture information on op
     dispatch, execution and retirement, branch prediction, L1 and L2
     cache activity, TLB activity, etc

   - Mark L1D_CACHE_INVAL impacted by errata for ARM64's AmpereOne/
     AmpereOneX

  Miscellaneous:

   - Sync header copies with the kernel sources

   - Move some header copies used only for generating translation string
     tables for ioctl cmds and other syscall integer arguments to a new
     directory under tools/perf/beauty/, to separate from copies in
     tools/include/ that are used to build the tools

   - Introduce scrape script for several syscall 'flags'/'mask'
     arguments

   - Improve cpumap utilization, fixing up pairing of refcounts, using
     the right iterators (perf_cpu_map__for_each_cpu), etc

   - Give more details about raw event encodings in 'perf list', show
     tracepoint encoding in the detailed output

   - Refactor the DSOs handling code, reducing memory usage

   - Document the BPF event modifier and add a 'perf test' for it

   - Improve the event parser, better error messages and add further
     'perf test's for it

   - Add reference count checking to 'struct comm_str' and 'struct
     mem_info'

   - Make ARM64's 'perf test' entries for the Neoverse N1 more robust

   - Tweak the ARM64's Coresight 'perf test's

   - Improve ARM64's CoreSight ETM version detection and error reporting

   - Fix handling of symbols when using kcore

   - Fix PAI (Processor Activity Instrumentation) counter names for s390
     virtual machines in 'perf report'

   - Fix -g/--call-graph option failure in 'perf sched timehist'

   - Add LIBTRACEEVENT_DIR build option to allow building with
     libtraceevent installed in non-standard directories, such as when
     doing cross builds

   - Various 'perf test' and 'perf bench' fixes

   - Improve 'perf probe' error message for long C++ probe names"

* tag 'perf-tools-for-v6.10-1-2024-05-21' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (260 commits)
  tools lib subcmd: Show parent options in help
  perf pmu: Count sys and cpuid JSON events separately
  perf stat: Don't display metric header for non-leader uncore events
  perf annotate-data: Ensure the number of type histograms
  perf annotate: Fix segfault on sample histogram
  perf daemon: Fix file leak in daemon_session__control
  libsubcmd: Fix parse-options memory leak
  perf lock: Avoid memory leaks from strdup()
  perf sched: Rename 'switches' column header to 'count' and add usage description, options for latency
  perf tools: Ignore deleted cgroups
  perf parse: Allow tracepoint names to start with digits
  perf parse-events: Add new 'fake_tp' parameter for tests
  perf parse-events: pass parse_state to add_tracepoint
  perf symbols: Fix ownership of string in dso__load_vmlinux()
  perf symbols: Update kcore map before merging in remaining symbols
  perf maps: Re-use __maps__free_maps_by_name()
  perf symbols: Remove map from list before updating addresses
  perf tracepoint: Don't scan all tracepoints to test if one exists
  perf dwarf-aux: Fix build with HAVE_DWARF_CFI_SUPPORT
  perf thread: Fixes to thread__new() related to initializing comm
  ...

1 files changed, 229 insertions, 62 deletions

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index f39cbbc1a7ec..888ce9912275 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -36,6 +36,18 @@ struct perf_pmu perf_pmu__fake = {
 
 #define UNIT_MAX_LEN	31 /* max length for event unit name */
 
+enum event_source {
+	/* An event loaded from /sys/devices/<pmu>/events. */
+	EVENT_SRC_SYSFS,
+	/* An event loaded from a CPUID matched json file. */
+	EVENT_SRC_CPU_JSON,
+	/*
+	 * An event loaded from a /sys/devices/<pmu>/identifier matched json
+	 * file.
+	 */
+	EVENT_SRC_SYS_JSON,
+};
+
 /**
  * struct perf_pmu_alias - An event either read from sysfs or builtin in
  * pmu-events.c, created by parsing the pmu-events json files.
@@ -182,7 +194,7 @@ static void perf_pmu_format__load(const struct perf_pmu *pmu, struct perf_pmu_fo
  * Parse & process all the sysfs attributes located under
  * the directory specified in 'dir' parameter.
  */
-int perf_pmu__format_parse(struct perf_pmu *pmu, int dirfd, bool eager_load)
+static int perf_pmu__format_parse(struct perf_pmu *pmu, int dirfd, bool eager_load)
 {
 	struct dirent *evt_ent;
 	DIR *format_dir;
@@ -232,7 +244,7 @@ int perf_pmu__format_parse(struct perf_pmu *pmu, int dirfd, bool eager_load)
  * located at:
  * /sys/bus/event_source/devices/<dev>/format as sysfs group attributes.
  */
-static int pmu_format(struct perf_pmu *pmu, int dirfd, const char *name)
+static int pmu_format(struct perf_pmu *pmu, int dirfd, const char *name, bool eager_load)
 {
 	int fd;
 
@@ -241,7 +253,7 @@ static int pmu_format(struct perf_pmu *pmu, int dirfd, const char *name)
 		return 0;
 
 	/* it'll close the fd */
-	if (perf_pmu__format_parse(pmu, fd, /*eager_load=*/false))
+	if (perf_pmu__format_parse(pmu, fd, eager_load))
 		return -1;
 
 	return 0;
@@ -425,9 +437,30 @@ static struct perf_pmu_alias *perf_pmu__find_alias(struct perf_pmu *pmu,
 {
 	struct perf_pmu_alias *alias;
 
-	if (load && !pmu->sysfs_aliases_loaded)
-		pmu_aliases_parse(pmu);
+	if (load && !pmu->sysfs_aliases_loaded) {
+		bool has_sysfs_event;
+		char event_file_name[FILENAME_MAX + 8];
+
+		/*
+		 * Test if alias/event 'name' exists in the PMU's sysfs/events
+		 * directory. If not skip parsing the sysfs aliases. Sysfs event
+		 * name must be all lower or all upper case.
+		 */
+		scnprintf(event_file_name, sizeof(event_file_name), "events/%s", name);
+		for (size_t i = 7, n = 7 + strlen(name); i < n; i++)
+			event_file_name[i] = tolower(event_file_name[i]);
+
+		has_sysfs_event = perf_pmu__file_exists(pmu, event_file_name);
+		if (!has_sysfs_event) {
+			for (size_t i = 7, n = 7 + strlen(name); i < n; i++)
+				event_file_name[i] = toupper(event_file_name[i]);
+
+			has_sysfs_event = perf_pmu__file_exists(pmu, event_file_name);
+		}
+		if (has_sysfs_event)
+			pmu_aliases_parse(pmu);
 
+	}
 	list_for_each_entry(alias, &pmu->aliases, list) {
 		if (!strcasecmp(alias->name, name))
 			return alias;
@@ -500,7 +533,7 @@ static int update_alias(const struct pmu_event *pe,
 
 static int perf_pmu__new_alias(struct perf_pmu *pmu, const char *name,
 				const char *desc, const char *val, FILE *val_fd,
-				const struct pmu_event *pe)
+			        const struct pmu_event *pe, enum event_source src)
 {
 	struct perf_pmu_alias *alias;
 	int ret;
@@ -518,7 +551,8 @@ static int perf_pmu__new_alias(struct perf_pmu *pmu, const char *name,
 		unit = pe->unit;
 		perpkg = pe->perpkg;
 		deprecated = pe->deprecated;
-		pmu_name = pe->pmu;
+		if (pe->pmu && strcmp(pe->pmu, "default_core"))
+			pmu_name = pe->pmu;
 	}
 
 	alias = zalloc(sizeof(*alias));
@@ -552,25 +586,30 @@ static int perf_pmu__new_alias(struct perf_pmu *pmu, const char *name,
 		}
 		snprintf(alias->unit, sizeof(alias->unit), "%s", unit);
 	}
-	if (!pe) {
-		/* Update an event from sysfs with json data. */
-		struct update_alias_data data = {
-			.pmu = pmu,
-			.alias = alias,
-		};
-
+	switch (src) {
+	default:
+	case EVENT_SRC_SYSFS:
 		alias->from_sysfs = true;
 		if (pmu->events_table) {
+			/* Update an event from sysfs with json data. */
+			struct update_alias_data data = {
+				.pmu = pmu,
+				.alias = alias,
+			};
 			if (pmu_events_table__find_event(pmu->events_table, pmu, name,
 							 update_alias, &data) == 0)
-				pmu->loaded_json_aliases++;
+				pmu->cpu_json_aliases++;
 		}
-	}
-
-	if (!pe)
 		pmu->sysfs_aliases++;
-	else
-		pmu->loaded_json_aliases++;
+		break;
+	case  EVENT_SRC_CPU_JSON:
+		pmu->cpu_json_aliases++;
+		break;
+	case  EVENT_SRC_SYS_JSON:
+		pmu->sys_json_aliases++;
+		break;
+
+	}
 	list_add_tail(&alias->list, &pmu->aliases);
 	return 0;
 }
@@ -596,33 +635,18 @@ static inline bool pmu_alias_info_file(const char *name)
  * Reading the pmu event aliases definition, which should be located at:
  * /sys/bus/event_source/devices/<dev>/events as sysfs group attributes.
  */
-static int pmu_aliases_parse(struct perf_pmu *pmu)
+static int __pmu_aliases_parse(struct perf_pmu *pmu, int events_dir_fd)
 {
-	char path[PATH_MAX];
 	struct dirent *evt_ent;
 	DIR *event_dir;
-	size_t len;
-	int fd, dir_fd;
 
-	len = perf_pmu__event_source_devices_scnprintf(path, sizeof(path));
-	if (!len)
-		return 0;
-	scnprintf(path + len, sizeof(path) - len, "%s/events", pmu->name);
-
-	dir_fd = open(path, O_DIRECTORY);
-	if (dir_fd == -1) {
-		pmu->sysfs_aliases_loaded = true;
-		return 0;
-	}
-
-	event_dir = fdopendir(dir_fd);
-	if (!event_dir){
-		close (dir_fd);
+	event_dir = fdopendir(events_dir_fd);
+	if (!event_dir)
 		return -EINVAL;
-	}
 
 	while ((evt_ent = readdir(event_dir))) {
 		char *name = evt_ent->d_name;
+		int fd;
 		FILE *file;
 
 		if (!strcmp(name, ".") || !strcmp(name, ".."))
@@ -634,7 +658,7 @@ static int pmu_aliases_parse(struct perf_pmu *pmu)
 		if (pmu_alias_info_file(name))
 			continue;
 
-		fd = openat(dir_fd, name, O_RDONLY);
+		fd = openat(events_dir_fd, name, O_RDONLY);
 		if (fd == -1) {
 			pr_debug("Cannot open %s\n", name);
 			continue;
@@ -646,17 +670,57 @@ static int pmu_aliases_parse(struct perf_pmu *pmu)
 		}
 
 		if (perf_pmu__new_alias(pmu, name, /*desc=*/ NULL,
-					/*val=*/ NULL, file, /*pe=*/ NULL) < 0)
+					/*val=*/ NULL, file, /*pe=*/ NULL,
+					EVENT_SRC_SYSFS) < 0)
 			pr_debug("Cannot set up %s\n", name);
 		fclose(file);
 	}
 
 	closedir(event_dir);
-	close (dir_fd);
 	pmu->sysfs_aliases_loaded = true;
 	return 0;
 }
 
+static int pmu_aliases_parse(struct perf_pmu *pmu)
+{
+	char path[PATH_MAX];
+	size_t len;
+	int events_dir_fd, ret;
+
+	if (pmu->sysfs_aliases_loaded)
+		return 0;
+
+	len = perf_pmu__event_source_devices_scnprintf(path, sizeof(path));
+	if (!len)
+		return 0;
+	scnprintf(path + len, sizeof(path) - len, "%s/events", pmu->name);
+
+	events_dir_fd = open(path, O_DIRECTORY);
+	if (events_dir_fd == -1) {
+		pmu->sysfs_aliases_loaded = true;
+		return 0;
+	}
+	ret = __pmu_aliases_parse(pmu, events_dir_fd);
+	close(events_dir_fd);
+	return ret;
+}
+
+static int pmu_aliases_parse_eager(struct perf_pmu *pmu, int sysfs_fd)
+{
+	char path[FILENAME_MAX + 7];
+	int ret, events_dir_fd;
+
+	scnprintf(path, sizeof(path), "%s/events", pmu->name);
+	events_dir_fd = openat(sysfs_fd, path, O_DIRECTORY, 0);
+	if (events_dir_fd == -1) {
+		pmu->sysfs_aliases_loaded = true;
+		return 0;
+	}
+	ret = __pmu_aliases_parse(pmu, events_dir_fd);
+	close(events_dir_fd);
+	return ret;
+}
+
 static int pmu_alias_terms(struct perf_pmu_alias *alias, int err_loc, struct list_head *terms)
 {
 	struct parse_events_term *term, *cloned;
@@ -900,7 +964,8 @@ static int pmu_add_cpu_aliases_map_callback(const struct pmu_event *pe,
 {
 	struct perf_pmu *pmu = vdata;
 
-	perf_pmu__new_alias(pmu, pe->name, pe->desc, pe->event, /*val_fd=*/ NULL, pe);
+	perf_pmu__new_alias(pmu, pe->name, pe->desc, pe->event, /*val_fd=*/ NULL,
+			    pe, EVENT_SRC_CPU_JSON);
 	return 0;
 }
 
@@ -935,13 +1000,14 @@ static int pmu_add_sys_aliases_iter_fn(const struct pmu_event *pe,
 		return 0;
 
 	if (pmu_uncore_alias_match(pe->pmu, pmu->name) &&
-			pmu_uncore_identifier_match(pe->compat, pmu->id)) {
+	    pmu_uncore_identifier_match(pe->compat, pmu->id)) {
 		perf_pmu__new_alias(pmu,
 				pe->name,
 				pe->desc,
 				pe->event,
 				/*val_fd=*/ NULL,
-				pe);
+				pe,
+				EVENT_SRC_SYS_JSON);
 	}
 
 	return 0;
@@ -993,7 +1059,8 @@ perf_pmu__arch_init(struct perf_pmu *pmu)
 		pmu->mem_events = perf_mem_events;
 }
 
-struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const char *name)
+struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const char *name,
+				  bool eager_load)
 {
 	struct perf_pmu *pmu;
 	__u32 type;
@@ -1022,7 +1089,7 @@ struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const char
 	 * type value and format definitions. Load both right
 	 * now.
 	 */
-	if (pmu_format(pmu, dirfd, name))
+	if (pmu_format(pmu, dirfd, name, eager_load))
 		goto err;
 
 	pmu->is_core = is_pmu_core(name);
@@ -1035,11 +1102,20 @@ struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const char
 	pmu->max_precise = pmu_max_precise(dirfd, pmu);
 	pmu->alias_name = pmu_find_alias_name(pmu, dirfd);
 	pmu->events_table = perf_pmu__find_events_table(pmu);
+	/*
+	 * Load the sys json events/aliases when loading the PMU as each event
+	 * may have a different compat regular expression. We therefore can't
+	 * know the number of sys json events/aliases without computing the
+	 * regular expressions for them all.
+	 */
 	pmu_add_sys_aliases(pmu);
 	list_add_tail(&pmu->list, pmus);
 
 	perf_pmu__arch_init(pmu);
 
+	if (eager_load)
+		pmu_aliases_parse_eager(pmu, dirfd);
+
 	return pmu;
 err:
 	zfree(&pmu->name);
@@ -1602,6 +1678,62 @@ bool perf_pmu__has_format(const struct perf_pmu *pmu, const char *name)
 	return false;
 }
 
+int perf_pmu__for_each_format(struct perf_pmu *pmu, void *state, pmu_format_callback cb)
+{
+	static const char *const terms[] = {
+		"config=0..0xffffffffffffffff",
+		"config1=0..0xffffffffffffffff",
+		"config2=0..0xffffffffffffffff",
+		"config3=0..0xffffffffffffffff",
+		"name=string",
+		"period=number",
+		"freq=number",
+		"branch_type=(u|k|hv|any|...)",
+		"time",
+		"call-graph=(fp|dwarf|lbr)",
+		"stack-size=number",
+		"max-stack=number",
+		"nr=number",
+		"inherit",
+		"no-inherit",
+		"overwrite",
+		"no-overwrite",
+		"percore",
+		"aux-output",
+		"aux-sample-size=number",
+	};
+	struct perf_pmu_format *format;
+	int ret;
+
+	/*
+	 * max-events and driver-config are missing above as are the internal
+	 * types user, metric-id, raw, legacy cache and hardware. Assert against
+	 * the enum parse_events__term_type so they are kept in sync.
+	 */
+	_Static_assert(ARRAY_SIZE(terms) == __PARSE_EVENTS__TERM_TYPE_NR - 6,
+		       "perf_pmu__for_each_format()'s terms must be kept in sync with enum parse_events__term_type");
+	list_for_each_entry(format, &pmu->format, list) {
+		perf_pmu_format__load(pmu, format);
+		ret = cb(state, format->name, (int)format->value, format->bits);
+		if (ret)
+			return ret;
+	}
+	if (!pmu->is_core)
+		return 0;
+
+	for (size_t i = 0; i < ARRAY_SIZE(terms); i++) {
+		int config = PERF_PMU_FORMAT_VALUE_CONFIG;
+
+		if (i < PERF_PMU_FORMAT_VALUE_CONFIG_END)
+			config = i;
+
+		ret = cb(state, terms[i], config, /*bits=*/NULL);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
 bool is_pmu_core(const char *name)
 {
 	return !strcmp(name, "cpu") || !strcmp(name, "cpum_cf") || is_sysfs_pmu_core(name);
@@ -1632,15 +1764,15 @@ size_t perf_pmu__num_events(struct perf_pmu *pmu)
 {
 	size_t nr;
 
-	if (!pmu->sysfs_aliases_loaded)
-		pmu_aliases_parse(pmu);
-
-	nr = pmu->sysfs_aliases;
+	pmu_aliases_parse(pmu);
+	nr = pmu->sysfs_aliases + pmu->sys_json_aliases;;
 
 	if (pmu->cpu_aliases_added)
-		 nr += pmu->loaded_json_aliases;
+		 nr += pmu->cpu_json_aliases;
 	else if (pmu->events_table)
-		nr += pmu_events_table__num_events(pmu->events_table, pmu) - pmu->loaded_json_aliases;
+		nr += pmu_events_table__num_events(pmu->events_table, pmu) - pmu->cpu_json_aliases;
+	else
+		assert(pmu->cpu_json_aliases == 0);
 
 	return pmu->selectable ? nr + 1 : nr;
 }
@@ -1693,11 +1825,16 @@ int perf_pmu__for_each_event(struct perf_pmu *pmu, bool skip_duplicate_pmus,
 	struct strbuf sb;
 
 	strbuf_init(&sb, /*hint=*/ 0);
+	pmu_aliases_parse(pmu);
 	pmu_add_cpu_aliases(pmu);
 	list_for_each_entry(event, &pmu->aliases, list) {
 		size_t buf_used;
+		int pmu_name_len;
 
 		info.pmu_name = event->pmu_name ?: pmu->name;
+		pmu_name_len = skip_duplicate_pmus
+			? pmu_name_len_no_suffix(info.pmu_name, /*num=*/NULL)
+			: (int)strlen(info.pmu_name);
 		info.alias = NULL;
 		if (event->desc) {
 			info.name = event->name;
@@ -1722,7 +1859,7 @@ int perf_pmu__for_each_event(struct perf_pmu *pmu, bool skip_duplicate_pmus,
 		info.encoding_desc = buf + buf_used;
 		parse_events_terms__to_strbuf(&event->terms, &sb);
 		buf_used += snprintf(buf + buf_used, sizeof(buf) - buf_used,
-				"%s/%s/", info.pmu_name, sb.buf) + 1;
+				"%.*s/%s/", pmu_name_len, info.pmu_name, sb.buf) + 1;
 		info.topic = event->topic;
 		info.str = sb.buf;
 		info.deprecated = event->deprecated;
@@ -2003,18 +2140,29 @@ void perf_pmu__warn_invalid_config(struct perf_pmu *pmu, __u64 config,
 		   name ?: "N/A", buf, config_name, config);
 }
 
-int perf_pmu__match(const char *pattern, const char *name, const char *tok)
+bool perf_pmu__match(const struct perf_pmu *pmu, const char *tok)
 {
-	if (!name)
-		return -1;
+	const char *name = pmu->name;
+	bool need_fnmatch = strchr(tok, '*') != NULL;
 
-	if (fnmatch(pattern, name, 0))
-		return -1;
+	if (!strncmp(tok, "uncore_", 7))
+		tok += 7;
+	if (!strncmp(name, "uncore_", 7))
+		name += 7;
 
-	if (tok && !perf_pmu__match_ignoring_suffix(name, tok))
-		return -1;
+	if (perf_pmu__match_ignoring_suffix(name, tok) ||
+	    (need_fnmatch && !fnmatch(tok, name, 0)))
+		return true;
 
-	return 0;
+	name = pmu->alias_name;
+	if (!name)
+		return false;
+
+	if (!strncmp(name, "uncore_", 7))
+		name += 7;
+
+	return perf_pmu__match_ignoring_suffix(name, tok) ||
+		(need_fnmatch && !fnmatch(tok, name, 0));
 }
 
 double __weak perf_pmu__cpu_slots_per_cycle(void)
@@ -2085,3 +2233,22 @@ void perf_pmu__delete(struct perf_pmu *pmu)
 	zfree(&pmu->id);
 	free(pmu);
 }
+
+const char *perf_pmu__name_from_config(struct perf_pmu *pmu, u64 config)
+{
+	struct perf_pmu_alias *event;
+
+	if (!pmu)
+		return NULL;
+
+	pmu_aliases_parse(pmu);
+	pmu_add_cpu_aliases(pmu);
+	list_for_each_entry(event, &pmu->aliases, list) {
+		struct perf_event_attr attr = {.config = 0,};
+		int ret = perf_pmu__config(pmu, &attr, &event->terms, NULL);
+
+		if (ret == 0 && config == attr.config)
+			return event->name;
+	}
+	return NULL;
+}