From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752258AbbIJHDu (ORCPT <rfc822;w@1wt.eu>);
	Thu, 10 Sep 2015 03:03:50 -0400
Received: from mail-pa0-f43.google.com ([209.85.220.43]:36316 "EHLO
	mail-pa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1750741AbbIJHDr (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Thu, 10 Sep 2015 03:03:47 -0400
Date: Thu, 10 Sep 2015 16:00:30 +0900
From: Namhyung Kim <namhyung@kernel.org>
To: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
        lkml <linux-kernel@vger.kernel.org>, David Ahern <dsahern@gmail.com>,
        Ingo Molnar <mingo@kernel.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Matt Fleming <matt@codeblueprint.co.uk>,
        =?utf-8?Q?Rapha=C3=ABl?= Beamonte <raphael.beamonte@gmail.com>
Subject: Re: [PATCH 5/5] perf tools: Enhance parsing events tracepoint error
 output
Message-ID: <20150910070030.GB18425@danjae.kornet>
References: <1441615087-13886-1-git-send-email-jolsa@kernel.org>
 <1441615087-13886-6-git-send-email-jolsa@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <1441615087-13886-6-git-send-email-jolsa@kernel.org>
User-Agent: Mutt/1.5.23+102 (2ca89bed6448) (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Mon, Sep 07, 2015 at 10:38:07AM +0200, Jiri Olsa wrote:
> Enhancing parsing events tracepoint error output. Adding
> more verbose output when the tracepoint is not found or
> the tracing event path cannot be access.
> 
>   $ sudo perf record -e sched:sched_krava ls
>   event syntax error: 'sched:sched_krava'
>                        \___ unknown tracepoint
> 
>   Error:  File /sys/kernel/debug/tracing//tracing/events/sched/sched_krava not found.
>   Hint:   Perhaps this kernel misses some CONFIG_ setting to enable this feature?.
> 
>   Run 'perf list' for a list of valid events
>   ...
> 
>   $ perf record -e sched:sched_krava ls
>   event syntax error: 'sched:sched_krava'
>                        \___ can't access trace events
> 
>   Error:  No permissions to read /sys/kernel/debug/tracing//tracing/events/sched/sched_krava
>   Hint:   Try 'sudo mount -o remount,mode=755 /sys/kernel/debug'

What about tracefs?  On my system, tracefs is mounted on
/sys/kernel/debug/tracing thus I cannot access trace events after
remounting debugfs with mode=755.

Also, IIRC tracepoint events adds PERF_SAMPLE_RAW bit automatically,
and it requires perf_event_paranoid being -1 for non-root user, right?

Thanks,
Namhyung