From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751439Ab3KOMpn (ORCPT ); Fri, 15 Nov 2013 07:45:43 -0500 Received: from mga09.intel.com ([134.134.136.24]:4870 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750960Ab3KOMpi (ORCPT ); Fri, 15 Nov 2013 07:45:38 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.93,535,1378882800"; d="scan'208";a="435794611" Message-ID: <5286191C.1090601@intel.com> Date: Fri, 15 Nov 2013 14:52:44 +0200 From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: Peter Zijlstra CC: Ingo Molnar , Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org, David Ahern , Frederic Weisbecker , Ingo Molnar , Jiri Olsa , Mike Galbraith , Namhyung Kim , Paul Mackerras , Stephane Eranian , Arnaldo Carvalho de Melo , Namhyung Kim Subject: Re: [PATCH 10/10] perf record: Add an option to force per-cpu mmaps References: <1384460715-23198-1-git-send-email-acme@infradead.org> <1384460715-23198-11-git-send-email-acme@infradead.org> <20131115060643.GA9237@gmail.com> <5285FECE.7020802@intel.com> <20131115111032.GA18647@gmail.com> <52860529.50200@intel.com> <20131115115629.GB19004@gmail.com> <20131115120329.GH2965@twins.programming.kicks-ass.net> In-Reply-To: <20131115120329.GH2965@twins.programming.kicks-ass.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15/11/13 14:03, Peter Zijlstra wrote: > On Fri, Nov 15, 2013 at 12:56:29PM +0100, Ingo Molnar wrote: >> So, here's the current status quo, there's 4 basic types of profiling >> that 99% of the people are using, in order of popularity: >> >> perf record >> perf record -a sleep N >> perf record -p >> perf record -t >> >> The first two (which I'd guess comprise about 95% of real-world usage) >> have inheritance enabled. >> >> The last two (-p/-t) have inheritance disabled by default. > > Yes, and I would expect it to be disabled for the TID option as you > explicitly select a single threads. So you want -t to imply -i ? That means if you want inheritance you have to do -t --no-no-inherit Or do you want another option --inherit > > For the process wide thing it would make sense to enable inheritance by > default though. > > So the big trade-off is that for single threaded processes which do not > fork you now have a single buffer, whereas with the inheritance option > you'll end up with nr_cpus buffers by default. > > I suppose for most normal people that's not really an issue; and I > suppose all people with silly large machines already pay extra attention > -- but at least make it explicit and very clear that this is so. > > > >