perf list: Sort the output of 'perf list' to view more clearly

Sort the output according to ASCII character list (using strcmp), which
supports both number sequence and alphabet sequence.

Example:

Before this patch:

 $ perf list

 List of pre-defined events (to be used in -e):
   cpu-cycles OR cycles                               [Hardware event]
   instructions                                       [Hardware event]
   cache-references                                   [Hardware event]
   cache-misses                                       [Hardware event]
   branch-instructions OR branches                    [Hardware event]
   branch-misses                                      [Hardware event]
   bus-cycles                                         [Hardware event]
   ...                                                ...

   jbd2:jbd2_start_commit                             [Tracepoint event]
   jbd2:jbd2_commit_locking                           [Tracepoint event]
   jbd2:jbd2_run_stats                                [Tracepoint event]
   block:block_rq_issue                               [Tracepoint event]
   block:block_bio_complete                           [Tracepoint event]
   block:block_bio_backmerge                          [Tracepoint event]
   block:block_getrq                                  [Tracepoint event]
   ...                                                ...

After this patch:

 $ perf list

 List of pre-defined events (to be used in -e):
   branch-instructions OR branches                    [Hardware event]
   branch-misses                                      [Hardware event]
   bus-cycles                                         [Hardware event]
   cache-misses                                       [Hardware event]
   cache-references                                   [Hardware event]
   cpu-cycles OR cycles                               [Hardware event]
   instructions                                       [Hardware event]
   ...                                                ...

   block:block_bio_backmerge                          [Tracepoint event]
   block:block_bio_complete                           [Tracepoint event]
   block:block_getrq                                  [Tracepoint event]
   block:block_rq_issue                               [Tracepoint event]
   jbd2:jbd2_commit_locking                           [Tracepoint event]
   jbd2:jbd2_run_stats                                [Tracepoint event]
   jbd2:jbd2_start_commit                             [Tracepoint event]
   ...                                                ...

Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1425032491-20224-2-git-send-email-yunlong.song@huawei.com
[ Don't forget closedir({sys,evt}_dir) when handling errors ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/parse-events.c

@@ -1089,6 +1089,14 @@ static const char * const event_type_descriptors[] = {
 	"Hardware breakpoint",
 };
 
+static int cmp_string(const void *a, const void *b)
+{
+	const char * const *as = a;
+	const char * const *bs = b;
+
+	return strcmp(*as, *bs);
+}
+
 /*
  * Print the events from <debugfs_mount_point>/tracing/events
  */
@@ -1100,11 +1108,21 @@ void print_tracepoint_events(const char *subsys_glob, const char *event_glob,
 	struct dirent *sys_next, *evt_next, sys_dirent, evt_dirent;
 	char evt_path[MAXPATHLEN];
 	char dir_path[MAXPATHLEN];
+	char **evt_list = NULL;
+	unsigned int evt_i = 0, evt_num = 0;
+	bool evt_num_known = false;
 
+restart:
 	sys_dir = opendir(tracing_events_path);
 	if (!sys_dir)
 		return;
 
+	if (evt_num_known) {
+		evt_list = zalloc(sizeof(char *) * evt_num);
+		if (!evt_list)
+			goto out_close_sys_dir;
+	}
+
 	for_each_subsystem(sys_dir, sys_dirent, sys_next) {
 		if (subsys_glob != NULL &&
 		    !strglobmatch(sys_dirent.d_name, subsys_glob))
@@ -1121,19 +1139,56 @@ void print_tracepoint_events(const char *subsys_glob, const char *event_glob,
 			    !strglobmatch(evt_dirent.d_name, event_glob))
 				continue;
 
-			if (name_only) {
-				printf("%s:%s ", sys_dirent.d_name, evt_dirent.d_name);
+			if (!evt_num_known) {
+				evt_num++;
 				continue;
 			}
 
 			snprintf(evt_path, MAXPATHLEN, "%s:%s",
 				 sys_dirent.d_name, evt_dirent.d_name);
-			printf("  %-50s [%s]\n", evt_path,
-				event_type_descriptors[PERF_TYPE_TRACEPOINT]);
+
+			evt_list[evt_i] = strdup(evt_path);
+			if (evt_list[evt_i] == NULL)
+				goto out_close_evt_dir;
+			evt_i++;
 		}
 		closedir(evt_dir);
 	}
 	closedir(sys_dir);
+
+	if (!evt_num_known) {
+		evt_num_known = true;
+		goto restart;
+	}
+	qsort(evt_list, evt_num, sizeof(char *), cmp_string);
+	evt_i = 0;
+	while (evt_i < evt_num) {
+		if (name_only) {
+			printf("%s ", evt_list[evt_i++]);
+			continue;
+		}
+		printf("  %-50s [%s]\n", evt_list[evt_i++],
+				event_type_descriptors[PERF_TYPE_TRACEPOINT]);
+	}
+	if (evt_num)
+		printf("\n");
+
+out_free:
+	evt_num = evt_i;
+	for (evt_i = 0; evt_i < evt_num; evt_i++)
+		zfree(&evt_list[evt_i]);
+	zfree(&evt_list);
+	return;
+
+out_close_evt_dir:
+	closedir(evt_dir);
+out_close_sys_dir:
+	closedir(sys_dir);
+
+	printf("FATAL: not enough memory to print %s\n",
+			event_type_descriptors[PERF_TYPE_TRACEPOINT]);
+	if (evt_list)
+		goto out_free;
 }
 
 /*
@@ -1218,20 +1273,61 @@ static void __print_events_type(u8 type, struct event_symbol *syms,
 				unsigned max)
 {
 	char name[64];
-	unsigned i;
+	unsigned int i, evt_i = 0, evt_num = 0;
+	char **evt_list = NULL;
+	bool evt_num_known = false;
+
+restart:
+	if (evt_num_known) {
+		evt_list = zalloc(sizeof(char *) * evt_num);
+		if (!evt_list)
+			goto out_enomem;
+		syms -= max;
+	}
 
 	for (i = 0; i < max ; i++, syms++) {
 		if (!is_event_supported(type, i))
 			continue;
 
+		if (!evt_num_known) {
+			evt_num++;
+			continue;
+		}
+
 		if (strlen(syms->alias))
 			snprintf(name, sizeof(name),  "%s OR %s",
 				 syms->symbol, syms->alias);
 		else
 			snprintf(name, sizeof(name), "%s", syms->symbol);
 
-		printf("  %-50s [%s]\n", name, event_type_descriptors[type]);
+		evt_list[evt_i] = strdup(name);
+		if (evt_list[evt_i] == NULL)
+			goto out_enomem;
+		evt_i++;
+	}
+
+	if (!evt_num_known) {
+		evt_num_known = true;
+		goto restart;
 	}
+	qsort(evt_list, evt_num, sizeof(char *), cmp_string);
+	evt_i = 0;
+	while (evt_i < evt_num)
+		printf("  %-50s [%s]\n", evt_list[evt_i++], event_type_descriptors[type]);
+	if (evt_num)
+		printf("\n");
+
+out_free:
+	evt_num = evt_i;
+	for (evt_i = 0; evt_i < evt_num; evt_i++)
+		zfree(&evt_list[evt_i]);
+	zfree(&evt_list);
+	return;
+
+out_enomem:
+	printf("FATAL: not enough memory to print %s\n", event_type_descriptors[type]);
+	if (evt_list)
+		goto out_free;
 }
 
 void print_events_type(u8 type)
@@ -1244,8 +1340,17 @@ void print_events_type(u8 type)
 
 int print_hwcache_events(const char *event_glob, bool name_only)
 {
-	unsigned int type, op, i, printed = 0;
+	unsigned int type, op, i, evt_i = 0, evt_num = 0;
 	char name[64];
+	char **evt_list = NULL;
+	bool evt_num_known = false;
+
+restart:
+	if (evt_num_known) {
+		evt_list = zalloc(sizeof(char *) * evt_num);
+		if (!evt_list)
+			goto out_enomem;
+	}
 
 	for (type = 0; type < PERF_COUNT_HW_CACHE_MAX; type++) {
 		for (op = 0; op < PERF_COUNT_HW_CACHE_OP_MAX; op++) {
@@ -1263,27 +1368,66 @@ int print_hwcache_events(const char *event_glob, bool name_only)
 							type | (op << 8) | (i << 16)))
 					continue;
 
-				if (name_only)
-					printf("%s ", name);
-				else
-					printf("  %-50s [%s]\n", name,
-					       event_type_descriptors[PERF_TYPE_HW_CACHE]);
-				++printed;
+				if (!evt_num_known) {
+					evt_num++;
+					continue;
+				}
+
+				evt_list[evt_i] = strdup(name);
+				if (evt_list[evt_i] == NULL)
+					goto out_enomem;
+				evt_i++;
 			}
 		}
 	}
 
-	if (printed)
+	if (!evt_num_known) {
+		evt_num_known = true;
+		goto restart;
+	}
+	qsort(evt_list, evt_num, sizeof(char *), cmp_string);
+	evt_i = 0;
+	while (evt_i < evt_num) {
+		if (name_only) {
+			printf("%s ", evt_list[evt_i++]);
+			continue;
+		}
+		printf("  %-50s [%s]\n", evt_list[evt_i++],
+				event_type_descriptors[PERF_TYPE_HW_CACHE]);
+	}
+	if (evt_num)
 		printf("\n");
-	return printed;
+
+out_free:
+	evt_num = evt_i;
+	for (evt_i = 0; evt_i < evt_num; evt_i++)
+		zfree(&evt_list[evt_i]);
+	zfree(&evt_list);
+	return evt_num;
+
+out_enomem:
+	printf("FATAL: not enough memory to print %s\n", event_type_descriptors[PERF_TYPE_HW_CACHE]);
+	if (evt_list)
+		goto out_free;
+	return evt_num;
 }
 
 static void print_symbol_events(const char *event_glob, unsigned type,
 				struct event_symbol *syms, unsigned max,
 				bool name_only)
 {
-	unsigned i, printed = 0;
+	unsigned int i, evt_i = 0, evt_num = 0;
 	char name[MAX_NAME_LEN];
+	char **evt_list = NULL;
+	bool evt_num_known = false;
+
+restart:
+	if (evt_num_known) {
+		evt_list = zalloc(sizeof(char *) * evt_num);
+		if (!evt_list)
+			goto out_enomem;
+		syms -= max;
+	}
 
 	for (i = 0; i < max; i++, syms++) {
 
@@ -1295,23 +1439,49 @@ static void print_symbol_events(const char *event_glob, unsigned type,
 		if (!is_event_supported(type, i))
 			continue;
 
-		if (name_only) {
-			printf("%s ", syms->symbol);
+		if (!evt_num_known) {
+			evt_num++;
 			continue;
 		}
 
-		if (strlen(syms->alias))
+		if (!name_only && strlen(syms->alias))
 			snprintf(name, MAX_NAME_LEN, "%s OR %s", syms->symbol, syms->alias);
 		else
 			strncpy(name, syms->symbol, MAX_NAME_LEN);
 
-		printf("  %-50s [%s]\n", name, event_type_descriptors[type]);
-
-		printed++;
+		evt_list[evt_i] = strdup(name);
+		if (evt_list[evt_i] == NULL)
+			goto out_enomem;
+		evt_i++;
 	}
 
-	if (printed)
+	if (!evt_num_known) {
+		evt_num_known = true;
+		goto restart;
+	}
+	qsort(evt_list, evt_num, sizeof(char *), cmp_string);
+	evt_i = 0;
+	while (evt_i < evt_num) {
+		if (name_only) {
+			printf("%s ", evt_list[evt_i++]);
+			continue;
+		}
+		printf("  %-50s [%s]\n", evt_list[evt_i++], event_type_descriptors[type]);
+	}
+	if (evt_num)
 		printf("\n");
+
+out_free:
+	evt_num = evt_i;
+	for (evt_i = 0; evt_i < evt_num; evt_i++)
+		zfree(&evt_list[evt_i]);
+	zfree(&evt_list);
+	return;
+
+out_enomem:
+	printf("FATAL: not enough memory to print %s\n", event_type_descriptors[type]);
+	if (evt_list)
+		goto out_free;
 }
 
 /*