perf list: Support long jevents descriptions

Previously we were dropping the useful longer descriptions that some
events have in the event list completely. This patch makes them appear with
perf list.

Old perf list:

baclears:
baclears.all
[Counts the number of baclears]

vs new:

perf list -v:
...
baclears:
baclears.all
[The BACLEARS event counts the number of times the front end is
resteered, mainly when the Branch Prediction Unit cannot provide
a correct prediction and this is corrected by the Branch Address
Calculator at the front end. The BACLEARS.ANY event counts the
number of baclears for any type of branch]

Signed-off-by: Andi Kleen <[e-mail]>
Signed-off-by: Sukadev Bhattiprolu <[e-mail]>
Acked-by: Ingo Molnar <[e-mail]>
Acked-by: Jiri Olsa <[e-mail]>
Cc: Madhavan Srinivasan <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: [e-mail]
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/Documentation/perf-list.txt

···
 SYNOPSIS
 --------
 [verse]
-'perf list' [--no-desc] [hw|sw|cache|tracepoint|pmu|event_glob]
+'perf list' [--no-desc] [--long-desc] [hw|sw|cache|tracepoint|pmu|event_glob]
 
 DESCRIPTION
 -----------
···
 -------
 --no-desc::
 Don't print descriptions.
+
+-v::
+--long-desc::
+Print longer event descriptions.
 
 
 [[EVENT_MODIFIERS]]

tools/perf/builtin-list.c

···
 {
 	int i;
 	bool raw_dump = false;
+	bool long_desc_flag = false;
 	struct option list_options[] = {
 		OPT_BOOLEAN(0, "raw-dump", &raw_dump, "Dump raw events"),
 		OPT_BOOLEAN('d', "desc", &desc_flag,
 			    "Print extra event descriptions. --no-desc to not print."),
+		OPT_BOOLEAN('v', "long-desc", &long_desc_flag,
+			    "Print longer event descriptions."),
 		OPT_END()
 	};
 	const char * const list_usage[] = {
-		"perf list [--no-desc] [hw|sw|cache|tracepoint|pmu|sdt|event_glob]",
+		"perf list [<options>] [hw|sw|cache|tracepoint|pmu|sdt|event_glob]",
 		NULL
 	};
 
···
 		printf("\nList of pre-defined events (to be used in -e):\n\n");
 
 	if (argc == 0) {
-		print_events(NULL, raw_dump, !desc_flag);
+		print_events(NULL, raw_dump, !desc_flag, long_desc_flag);
 		return 0;
 	}
 
···
 			 strcmp(argv[i], "hwcache") == 0)
 			print_hwcache_events(NULL, raw_dump);
 		else if (strcmp(argv[i], "pmu") == 0)
-			print_pmu_events(NULL, raw_dump, !desc_flag);
+			print_pmu_events(NULL, raw_dump, !desc_flag,
+						long_desc_flag);
 		else if (strcmp(argv[i], "sdt") == 0)
 			print_sdt_events(NULL, NULL, raw_dump);
 		else if ((sep = strchr(argv[i], ':')) != NULL) {
 			int sep_idx;
 
 			if (sep == NULL) {
-				print_events(argv[i], raw_dump, !desc_flag);
+				print_events(argv[i], raw_dump, !desc_flag,
+							long_desc_flag);
 				continue;
 			}
 			sep_idx = sep - argv[i];
···
 			print_symbol_events(s, PERF_TYPE_SOFTWARE,
 					    event_symbols_sw, PERF_COUNT_SW_MAX, raw_dump);
 			print_hwcache_events(s, raw_dump);
-			print_pmu_events(s, raw_dump, !desc_flag);
+			print_pmu_events(s, raw_dump, !desc_flag,
+						long_desc_flag);
 			print_tracepoint_events(NULL, s, raw_dump);
 			print_sdt_events(NULL, s, raw_dump);
 			free(s);

tools/perf/util/parse-events.c

···
 /*
  * Print the help text for the event symbols:
  */
-void print_events(const char *event_glob, bool name_only, bool quiet_flag)
+void print_events(const char *event_glob, bool name_only, bool quiet_flag,
+			bool long_desc)
 {
 	print_symbol_events(event_glob, PERF_TYPE_HARDWARE,
 			    event_symbols_hw, PERF_COUNT_HW_MAX, name_only);
···
 
 	print_hwcache_events(event_glob, name_only);
 
-	print_pmu_events(event_glob, name_only, quiet_flag);
+	print_pmu_events(event_glob, name_only, quiet_flag, long_desc);
 
 	if (event_glob != NULL)
 		return;

tools/perf/util/parse-events.h

···
 void parse_events_evlist_error(struct parse_events_evlist *data,
 			       int idx, const char *str);
 
-void print_events(const char *event_glob, bool name_only, bool quiet);
+void print_events(const char *event_glob, bool name_only, bool quiet,
+		  bool long_desc);
 
 struct event_symbol {
 	const char	*symbol;

tools/perf/util/pmu.c

···
 }
 
 static int __perf_pmu__new_alias(struct list_head *list, char *dir, char *name,
-				 char *desc, char *val)
+				 char *desc, char *val, char *long_desc)
 {
 	struct perf_pmu_alias *alias;
 	int ret;
···
 	}
 
 	alias->desc = desc ? strdup(desc) : NULL;
+	alias->long_desc = long_desc ? strdup(long_desc) :
+				desc ? strdup(desc) : NULL;
 
 	list_add_tail(&alias->list, list);
 
···
 
 	buf[ret] = 0;
 
-	return __perf_pmu__new_alias(list, dir, name, NULL, buf);
+	return __perf_pmu__new_alias(list, dir, name, NULL, buf, NULL);
 }
 
 static inline bool pmu_alias_info_file(char *name)
···
 
 		/* need type casts to override 'const' */
 		__perf_pmu__new_alias(head, NULL, (char *)pe->name,
-				(char *)pe->desc, (char *)pe->event);
+				(char *)pe->desc, (char *)pe->event,
+				(char *)pe->long_desc);
 	}
 
 out:
···
 	}
 }
 
-void print_pmu_events(const char *event_glob, bool name_only, bool quiet_flag)
+void print_pmu_events(const char *event_glob, bool name_only, bool quiet_flag,
+			bool long_desc)
 {
 	struct perf_pmu *pmu;
 	struct perf_pmu_alias *alias;
···
 			if (!aliases[j].name)
 				goto out_enomem;
 
-			aliases[j].desc = alias->desc;
+			aliases[j].desc = long_desc ? alias->long_desc :
+						alias->desc;
 			j++;
 		}
 		if (pmu->selectable &&

tools/perf/util/pmu.h

···
 struct perf_pmu_alias {
 	char *name;
 	char *desc;
+	char *long_desc;
 	struct list_head terms; /* HEAD struct parse_events_term -> list */
 	struct list_head list;  /* ELEM */
 	char unit[UNIT_MAX_LEN+1];
···
 
 struct perf_pmu *perf_pmu__scan(struct perf_pmu *pmu);
 
-void print_pmu_events(const char *event_glob, bool name_only, bool quiet);
+void print_pmu_events(const char *event_glob, bool name_only, bool quiet,
+		      bool long_desc);
 bool pmu_have_event(const char *pname, const char *name);
 
 int perf_pmu__scan_file(struct perf_pmu *pmu, const char *name, const char *fmt,