perf tools: Fix permission checks
The perf_event_open() system call returns EACCES if the user is
not root which results in a very confusing error message:
$ perf record -A -a -f
Error: perfcounter syscall returned with -1 (Permission denied)
Fatal: No CONFIG_PERF_EVENTS=y kernel support configured?
It turns out that's because perf tools are checking only for
EPERM. Fix that up to get a much better error message:
$ perf record -A -a -f
Fatal: Permission error - are you root?
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1257696066-4046-1-git-send-email-penberg@cs.helsinki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index a1b1d10..e23bc74 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -1027,7 +1027,7 @@
if (fd[i][counter] < 0) {
int err = errno;
- if (err == EPERM)
+ if (err == EPERM || err == EACCES)
die("No permission - are you root?\n");
/*
* If it's cycles then fall back to hrtimer