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 S1753474AbbKZUof (ORCPT <rfc822;w@1wt.eu>);
	Thu, 26 Nov 2015 15:44:35 -0500
Received: from mail.kernel.org ([198.145.29.136]:53209 "EHLO mail.kernel.org"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1752777AbbKZUoc (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Thu, 26 Nov 2015 15:44:32 -0500
Date: Thu, 26 Nov 2015 17:44:28 -0300
From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Jiri Olsa <jolsa@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>, Steven Rostedt <rostedt@goodmis.org>,
        lkml <linux-kernel@vger.kernel.org>, David Ahern <dsahern@gmail.com>,
        Ingo Molnar <mingo@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH 2/3] perf: Move exclude_kernel tracepoint check to init
 event
Message-ID: <20151126204428.GL28162@kernel.org>
References: <1448566489-25922-1-git-send-email-jolsa@kernel.org>
 <1448566489-25922-3-git-send-email-jolsa@kernel.org>
 <20151126194106.GH28162@kernel.org>
 <20151126194910.GA26579@krava.brq.redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20151126194910.GA26579@krava.brq.redhat.com>
X-Url: http://acmel.wordpress.com
User-Agent: Mutt/1.5.23 (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

Em Thu, Nov 26, 2015 at 08:49:10PM +0100, Jiri Olsa escreveu:
> On Thu, Nov 26, 2015 at 04:41:06PM -0300, Arnaldo Carvalho de Melo wrote:
> > Em Thu, Nov 26, 2015 at 08:34:48PM +0100, Jiri Olsa escreveu:
> > > We suppress events with attr::exclude_kernel set when
> > > the event is generated, so following capture will
> > > give no warning and produce no data:
> > > 
> > >   $ sudo perf record -e sched:sched_switch:u ls
> > >   $ sudo /perf script | wc -l
> > >   0
> > > 
> > > Checking the attr::exclude_kernel at the event init
> > > time and failing right away:
> > 
> > We can as well provide a better warning in the tooling side and don't
> > even ask this nonsensical combo to the kernel, right?
> 
> yep.. I'll update my todo ;-)

Thanks!
 
> > Arguably the kernel was doing what was asked for, its just that no
> > sched:sched_switch took place while in user space... ;-)
> 
> I think it's better to fail like that.. rather than spending
> time on figuring why my test did not give me any data ;-)

Up to peterz ;-)

- Arnaldo