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 c47831c..d3fb90b 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -387,6 +387,33 @@
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 @@
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 @@
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 @@
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;
}