From: Arnaldo Carvalho de Melo on
From: Arnaldo Carvalho de Melo <acme(a)>

[acme(a)mica linux-2.6-tip]$ perf record -a -f
Fatal: Permission error - are you root?
Consider tweaking /proc/sys/kernel/perf_event_paranoid.

[acme(a)mica linux-2.6-tip]$

Suggested-by: Ingo Molnar <mingo(a)>
Cc: Frédéric Weisbecker <fweisbec(a)>
Cc: Mike Galbraith <efault(a)>
Cc: Peter Zijlstra <a.p.zijlstra(a)>
Cc: Paul Mackerras <paulus(a)>
Signed-off-by: Arnaldo Carvalho de Melo <acme(a)>
tools/perf/builtin-record.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 3bf1409..b280ab5 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -283,7 +283,8 @@ try_again:
int err = errno;

if (err == EPERM || err == EACCES)
- die("Permission error - are you root?\n");
+ die("Permission error - are you root?\n"
+ "\t Consider tweaking /proc/sys/kernel/perf_event_paranoid.\n");
else if (err == ENODEV && profile_cpu != -1)
die("No such device - did you specify an out-of-range profile CPU?\n");


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