perf tools: Enhance parsing events tracepoint error output

Enhancing parsing events tracepoint error output. Adding
more verbose output when the tracepoint is not found or
the tracing event path cannot be access.

  $ sudo perf record -e sched:sched_krava ls
  event syntax error: 'sched:sched_krava'
                       \___ unknown tracepoint

  Error:  File /sys/kernel/debug/tracing//tracing/events/sched/sched_krava not found.
  Hint:   Perhaps this kernel misses some CONFIG_ setting to enable this feature?.

  Run 'perf list' for a list of valid events
  ...

  $ perf record -e sched:sched_krava ls
  event syntax error: 'sched:sched_krava'
                       \___ can't access trace events

  Error:  No permissions to read /sys/kernel/debug/tracing//tracing/events/sched/sched_krava
  Hint:   Try 'sudo mount -o remount,mode=755 /sys/kernel/debug'

  Run 'perf list' for a list of valid events
  ...

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Raphael Beamonte <raphael.beamonte@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1441615087-13886-6-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index c47831c47220aaffbd763792db5988e9b72cd812..d3fb90be6216d3e24cbb854cefecadc866b3e6c1 100644 (file)
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -387,6 +387,33 @@ int parse_events_add_cache(struct list_head *list, int *idx,
        return add_event(list, idx, &attr, name, NULL);
 }
 
+static void tracepoint_error(struct parse_events_error *error, int err,
+                            char *sys, char *name)
+{
+       char help[BUFSIZ];
+
+       /*
+        * We get error directly from syscall errno ( > 0),
+        * or from encoded pointer's error ( < 0).
+        */
+       err = abs(err);
+
+       switch (err) {
+       case EACCES:
+               error->str = strdup("can't access trace events");
+               break;
+       case ENOENT:
+               error->str = strdup("unknown tracepoint");
+               break;
+       default:
+               error->str = strdup("failed to add tracepoint");
+               break;
+       }
+
+       tracing_path__strerror_open_tp(err, help, sizeof(help), sys, name);
+       error->help = strdup(help);
+}
+
 static int add_tracepoint(struct list_head *list, int *idx,
                          char *sys_name, char *evt_name,
                          struct parse_events_error *error __maybe_unused)
@@ -394,8 +421,10 @@ static int add_tracepoint(struct list_head *list, int *idx,
        struct perf_evsel *evsel;
 
        evsel = perf_evsel__newtp_idx(sys_name, evt_name, (*idx)++);
-       if (IS_ERR(evsel))
+       if (IS_ERR(evsel)) {
+               tracepoint_error(error, PTR_ERR(evsel), sys_name, evt_name);
                return PTR_ERR(evsel);
+       }
 
        list_add_tail(&evsel->node, list);
        return 0;
@@ -413,7 +442,7 @@ static int add_tracepoint_multi_event(struct list_head *list, int *idx,
        snprintf(evt_path, MAXPATHLEN, "%s/%s", tracing_events_path, sys_name);
        evt_dir = opendir(evt_path);
        if (!evt_dir) {
-               perror("Can't open event dir");
+               tracepoint_error(error, errno, sys_name, evt_name);
                return -1;
        }
 
@@ -453,7 +482,7 @@ static int add_tracepoint_multi_sys(struct list_head *list, int *idx,
 
        events_dir = opendir(tracing_events_path);
        if (!events_dir) {
-               perror("Can't open event dir");
+               tracepoint_error(error, errno, sys_name, evt_name);
                return -1;
        }
 

diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
index 54a3004a8192fc1cf85ffab7e986315e0b892b7c..8bcc458684578227b5dbd56e3e4774dcb0930759 100644 (file)
--- a/tools/perf/util/parse-events.y
+++ b/tools/perf/util/parse-events.y
@@ -371,28 +371,30 @@ event_legacy_tracepoint:
 PE_NAME '-' PE_NAME ':' PE_NAME
 {
        struct parse_events_evlist *data = _data;
+       struct parse_events_error *error = data->error;
        struct list_head *list;
        char sys_name[128];
        snprintf(&sys_name, 128, "%s-%s", $1, $3);
 
        ALLOC_LIST(list);
-       ABORT_ON(parse_events_add_tracepoint(list, &data->idx, &sys_name, $5, data->error));
+       if (parse_events_add_tracepoint(list, &data->idx, &sys_name, $5, error)) {
+               if (error)
+                       error->idx = @1.first_column;
+               return -1;
+       }
        $$ = list;
 }
 |
 PE_NAME ':' PE_NAME
 {
        struct parse_events_evlist *data = _data;
+       struct parse_events_error *error = data->error;
        struct list_head *list;
 
        ALLOC_LIST(list);
-       if (parse_events_add_tracepoint(list, &data->idx, $1, $3, data->error)) {
-               struct parse_events_error *error = data->error;
-
-               if (error) {
+       if (parse_events_add_tracepoint(list, &data->idx, $1, $3, error)) {
+               if (error)
                        error->idx = @1.first_column;
-                       error->str = strdup("unknown tracepoint");
-               }
                return -1;
        }
        $$ = list;