[tip:perf/core] perf stat: Bail out on unsupported event config modifiers

[tip-bot for Wang Nan]

Commit-ID:  1669e509ea25e4e3e871d913d21b1cac4a96d1e8
Gitweb:     http://git.kernel.org/tip/1669e509ea25e4e3e871d913d21b1cac4a96d1e8
Author:     Wang Nan <wangnan0@xxxxxxxxxx>
AuthorDate: Fri, 19 Feb 2016 11:43:58 +0000
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Fri, 19 Feb 2016 19:12:49 -0300

perf stat: Bail out on unsupported event config modifiers

'perf stat' accepts some config terms but doesn't apply them. For
example:

  # perf stat -e 'instructions/no-inherit/' -e 'instructions/inherit/' bash
  # ls
  # exit

  Performance counter stats for 'bash':

         266258061      instructions/no-inherit/
         266258061      instructions/inherit/

       1.402183915 seconds time elapsed

The result is confusing, because user may expect the first
'instructions' event exclude the 'ls' command.

This patch forbid most of these config terms for 'perf stat'.

Result:

  # ./perf stat -e 'instructions/no-inherit/' -e 'instructions/inherit/' bash
  event syntax error: 'instructions/no-inherit/'
                       \___ 'no-inherit' is not usable in 'perf stat'
  ...

We can add blocked config terms back when 'perf stat' really supports them.

This patch also removes unavailable config term from error message:

  # ./perf stat -e 'instructions/badterm/' ls
  event syntax error: 'instructions/badterm/'
                                    \___ unknown term

  valid terms: config,config1,config2,name

  # ./perf stat -e 'cpu/badterm/' ls
  event syntax error: 'cpu/badterm/'
                           \___ unknown term

  valid terms: pc,any,inv,edge,cmask,event,in_tx,ldlat,umask,in_tx_cp,offcore_rsp,config,config1,config2,name

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Brendan Gregg <brendan.d.gregg@xxxxxxxxx>
Cc: Cody P Schafer <dev@xxxxxxxxxx>
Cc: He Kuang <hekuang@xxxxxxxxxx>
Cc: Jeremie Galarneau <jeremie.galarneau@xxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kirill Smelkov <kirr@xxxxxxxxxx>
Cc: Li Zefan <lizefan@xxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
Link: http://lkml.kernel.org/r/1455882283-79592-11-git-send-email-wangnan0@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/builtin-stat.c      |  1 +
 tools/perf/util/parse-events.c | 48 ++++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/parse-events.h |  1 +
 3 files changed, 50 insertions(+)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 86289df..8c0bc0f 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -1831,6 +1831,7 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
 	if (evsel_list == NULL)
 		return -ENOMEM;
 
+	parse_events__shrink_config_terms();
 	argc = parse_options_subcommand(argc, argv, stat_options, stat_subcommands,
 					(const char **) stat_usage,
 					PARSE_OPT_STOP_AT_NON_OPTION);
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index fd085d5..eb5df43 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -765,6 +765,41 @@ static const char *config_term_names[__PARSE_EVENTS__TERM_TYPE_NR] = {
 	[PARSE_EVENTS__TERM_TYPE_INHERIT]		= "inherit",
 };
 
+static bool config_term_shrinked;
+
+static bool
+config_term_avail(int term_type, struct parse_events_error *err)
+{
+	if (term_type < 0 || term_type >= __PARSE_EVENTS__TERM_TYPE_NR) {
+		err->str = strdup("Invalid term_type");
+		return false;
+	}
+	if (!config_term_shrinked)
+		return true;
+
+	switch (term_type) {
+	case PARSE_EVENTS__TERM_TYPE_CONFIG:
+	case PARSE_EVENTS__TERM_TYPE_CONFIG1:
+	case PARSE_EVENTS__TERM_TYPE_CONFIG2:
+	case PARSE_EVENTS__TERM_TYPE_NAME:
+		return true;
+	default:
+		if (!err)
+			return false;
+
+		/* term_type is validated so indexing is safe */
+		if (asprintf(&err->str, "'%s' is not usable in 'perf stat'",
+			     config_term_names[term_type]) < 0)
+			err->str = NULL;
+		return false;
+	}
+}
+
+void parse_events__shrink_config_terms(void)
+{
+	config_term_shrinked = true;
+}
+
 typedef int config_term_func_t(struct perf_event_attr *attr,
 			       struct parse_events_term *term,
 			       struct parse_events_error *err);
@@ -834,6 +869,17 @@ do {									   \
 		return -EINVAL;
 	}
 
+	/*
+	 * Check term availbility after basic checking so
+	 * PARSE_EVENTS__TERM_TYPE_USER can be found and filtered.
+	 *
+	 * If check availbility at the entry of this function,
+	 * user will see "'<sysfs term>' is not usable in 'perf stat'"
+	 * if an invalid config term is provided for legacy events
+	 * (for example, instructions/badterm/...), which is confusing.
+	 */
+	if (!config_term_avail(term->type_term, err))
+		return -EINVAL;
 	return 0;
 #undef CHECK_TYPE_VAL
 }
@@ -2125,6 +2171,8 @@ static void config_terms_list(char *buf, size_t buf_sz)
 	for (i = 0; i < __PARSE_EVENTS__TERM_TYPE_NR; i++) {
 		const char *name = config_term_names[i];
 
+		if (!config_term_avail(i, NULL))
+			continue;
 		if (!name)
 			continue;
 		if (name[0] == '<')
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index b50d50b..76151f9 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -105,6 +105,7 @@ struct parse_events_terms {
 	struct list_head *terms;
 };
 
+void parse_events__shrink_config_terms(void);
 int parse_events__is_hardcoded_term(struct parse_events_term *term);
 int parse_events_term__num(struct parse_events_term **term,
 			   int type_term, char *config, u64 num,