Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932082AbdGCQkF (ORCPT ); Mon, 3 Jul 2017 12:40:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:55914 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755102AbdGCQkE (ORCPT ); Mon, 3 Jul 2017 12:40:04 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AB91F22B56 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=acme@kernel.org Date: Mon, 3 Jul 2017 13:40:01 -0300 From: Arnaldo Carvalho de Melo To: Jiri Olsa Cc: Jiri Olsa , lkml , Ingo Molnar , Peter Zijlstra , Namhyung Kim , David Ahern , Thomas Richter Subject: Re: [PATCHv2 01/15] perf tools: Fix -n option Message-ID: <20170703164001.GC16278@kernel.org> References: <20170703145030.12903-1-jolsa@kernel.org> <20170703145030.12903-2-jolsa@kernel.org> <20170703145739.GA16278@kernel.org> <20170703151654.GA16010@krava> <20170703161003.GB16278@kernel.org> <20170703162228.GA22468@krava> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170703162228.GA22468@krava> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.8.0 (2017-02-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2122 Lines: 50 Em Mon, Jul 03, 2017 at 06:22:28PM +0200, Jiri Olsa escreveu: > On Mon, Jul 03, 2017 at 01:10:04PM -0300, Arnaldo Carvalho de Melo wrote: > > Em Mon, Jul 03, 2017 at 05:16:54PM +0200, Jiri Olsa escreveu: > > > On Mon, Jul 03, 2017 at 11:57:39AM -0300, Arnaldo Carvalho de Melo wrote: > > > > Em Mon, Jul 03, 2017 at 04:50:16PM +0200, Jiri Olsa escreveu: > > > > > The kernel fails to add a non sampling event event > > > > > with having precise_ip set. > > > > > > > > > > Make sure the precise_ip is 0 when using -n option > > > > > to create non sampling event in record. > > > > > > > > Ok, but how could that happen? What was the scenario? Which command? Can > > > > you provide a command line that causes the problem? > > > > > > [jolsa@krava perf]$ ./perf record -e cycles:ppp -n ls > > > Lowering default frequency rate to 3000. > > > Please consider tweaking /proc/sys/kernel/perf_event_max_sample_rate. > > > Error: > > > The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (cycles:pppu). > > > /bin/dmesg may provide additional information. > > > No CONFIG_PERF_EVENTS=y kernel support configured? > > > > > > v2 attached, thanks > > > > Ok, so the user asks for --no-samples but at the same time asks for > > precision equal to :ppp, we should stop right there and warn the user > > that that is not possible, instead of silently dropping off what the > > user explicitely asked. > > well I take this option more like debug/devel one.. you have > failing command line and want to investigate the kernel state > without having samples generated under your fingers > > can't see why would normal user need it > > > > > I'm cooking a few patches to allow that, then we can apply your patch, > > that, with the current set of users will never kick in :-) Take a look at: https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/commit/?h=perf/core&id=9f6e7e8bbb99feb6d721be7ccefb8c9139fa5abb and: https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/commit/?h=perf/core&id=f9a4297945a99b47f92b111b5b1802a3b295a1a7 Its in my perf/core branch now. - Arnaldo