perf test: Clarify some error reports in the open syscall test

Rebooted my devel machine, first thing I ran was perf test, that expects
debugfs to be mounted, test fails. Be more clear about it.

Also add missing newlines and add more informative message when
sys_perf_event_open fails.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 11 insertions, 7 deletions

diff --git a/tools/perf/builtin-test.c b/tools/perf/builtin-test.c
index 6c991529f62b..1c984342a579 100644
--- a/tools/perf/builtin-test.c
+++ b/tools/perf/builtin-test.c
@@ -268,24 +268,26 @@ static int test__open_syscall_event(void)
         int id = trace_event__id("sys_enter_open");
 
         if (id < 0) {
-                pr_debug("trace_event__id(\"sys_enter_open\") ");
+                pr_debug("is debugfs mounted on /sys/kernel/debug?\n");
                 return -1;
         }
 
         threads = thread_map__new(-1, getpid());
         if (threads == NULL) {
-                pr_debug("thread_map__new ");
+                pr_debug("thread_map__new\n");
                 return -1;
         }
 
         evsel = perf_evsel__new(PERF_TYPE_TRACEPOINT, id, 0);
         if (evsel == NULL) {
-                pr_debug("perf_evsel__new ");
+                pr_debug("perf_evsel__new\n");
                 goto out_thread_map_delete;
         }
 
         if (perf_evsel__open_per_thread(evsel, threads) < 0) {
-                pr_debug("perf_evsel__open_per_thread ");
+                pr_debug("failed to open counter: %s, "
+                         "tweak /proc/sys/kernel/perf_event_paranoid?\n",
+                         strerror(errno));
                 goto out_evsel_delete;
         }
 
@@ -295,13 +297,15 @@ static int test__open_syscall_event(void)
         }
 
         if (perf_evsel__read_on_cpu(evsel, 0, 0) < 0) {
-                pr_debug("perf_evsel__open_read_on_cpu ");
+                pr_debug("perf_evsel__open_read_on_cpu\n");
                 goto out_close_fd;
         }
 
-        if (evsel->counts->cpu[0].val != nr_open_calls)
-                pr_debug("perf_evsel__read_on_cpu: expected to intercept %d calls, got %Ld ",
+        if (evsel->counts->cpu[0].val != nr_open_calls) {
+                pr_debug("perf_evsel__read_on_cpu: expected to intercept %d calls, got %Ld\n",
                          nr_open_calls, evsel->counts->cpu[0].val);
+                goto out_close_fd;
+        }
         
         err = 0;
 out_close_fd: