perf lock record: improve message when tracepoints are not enabled

If CONFIG options required for perf-lock are not enabled then the
corresponding tracepoints will not be enabled. Currently, the message to
the user is:
  $ perf lock record -a -- sleep 1
  invalid or unsupported event: 'lock:lock_acquire'
  Run 'perf list' for a list of valid events

Improve the message with a suggestion on which CONFIG options are needed:
  $ perf lock record -a -- sleep 1
  tracepoint lock:lock_acquire is not enabled. Are CONFIG_LOCKDEP and CONFIG_LOCK_STAT enabled?

Suggested-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1344530137-25521-1-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 24 insertions, 5 deletions

diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index 3f8b9550a6ef..585aae2858b8 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -903,16 +903,19 @@ static const struct option lock_options[] = {
         OPT_END()
 };
 
+static const char * const lock_tracepoints[] = {
+        "lock:lock_acquire",    /* CONFIG_LOCKDEP */
+        "lock:lock_acquired",   /* CONFIG_LOCKDEP, CONFIG_LOCK_STAT */
+        "lock:lock_contended",  /* CONFIG_LOCKDEP, CONFIG_LOCK_STAT */
+        "lock:lock_release",    /* CONFIG_LOCKDEP */
+};
+
 static const char *record_args[] = {
         "record",
         "-R",
         "-f",
         "-m", "1024",
         "-c", "1",
-        "-e", "lock:lock_acquire",
-        "-e", "lock:lock_acquired",
-        "-e", "lock:lock_contended",
-        "-e", "lock:lock_release",
 };
 
 static int __cmd_record(int argc, const char **argv)
@@ -920,15 +923,31 @@ static int __cmd_record(int argc, const char **argv)
         unsigned int rec_argc, i, j;
         const char **rec_argv;
 
+        for (i = 0; i < ARRAY_SIZE(lock_tracepoints); i++) {
+                if (!is_valid_tracepoint(lock_tracepoints[i])) {
+                                pr_err("tracepoint %s is not enabled. "
+                                       "Are CONFIG_LOCKDEP and CONFIG_LOCK_STAT enabled?\n",
+                                       lock_tracepoints[i]);
+                                return 1;
+                }
+        }
+
         rec_argc = ARRAY_SIZE(record_args) + argc - 1;
-        rec_argv = calloc(rec_argc + 1, sizeof(char *));
+        /* factor of 2 is for -e in front of each tracepoint */
+        rec_argc += 2 * ARRAY_SIZE(lock_tracepoints);
 
+        rec_argv = calloc(rec_argc + 1, sizeof(char *));
         if (rec_argv == NULL)
                 return -ENOMEM;
 
         for (i = 0; i < ARRAY_SIZE(record_args); i++)
                 rec_argv[i] = strdup(record_args[i]);
 
+        for (j = 0; j < ARRAY_SIZE(lock_tracepoints); j++) {
+                rec_argv[i++] = "-e";
+                rec_argv[i++] = strdup(lock_tracepoints[j]);
+        }
+
         for (j = 1; j < (unsigned int)argc; j++, i++)
                 rec_argv[i] = argv[j];