perf_counter tools: Handle kernels with !CONFIG_PERF_COUNTER

If perf is run on a !CONFIG_PERF_COUNTER kernel right now it
bails out with no messages or with confusing messages.

Standardize this case some more and explain the situation.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 4 insertions, 4 deletions

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 1f8c97d5c32e..be1698f1189b 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -551,10 +551,6 @@ try_again:
         if (fd[i][counter] < 0) {
                 int err = errno;
 
-                if (verbose)
-                        error("sys_perf_counter_open() syscall returned with %d (%s)\n",
-                                fd[i][counter], strerror(err));
-
                 if (err == EPERM)
                         die("No permission - are you root?\n");
                 /*
@@ -572,6 +568,10 @@ try_again:
                         attr->config = PERF_COUNT_CPU_CLOCK;
                         goto try_again;
                 }
+                printf("\n");
+                error("perfcounter syscall returned with %d (%s)\n",
+                        fd[i][counter], strerror(err));
+                die("No CONFIG_PERF_COUNTERS=y kernel support configured?\n");
                 exit(-1);
         }
         assert(fd[i][counter] >= 0);