From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932571AbbLGOMt (ORCPT ); Mon, 7 Dec 2015 09:12:49 -0500 Received: from casper.infradead.org ([85.118.1.10]:49983 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932395AbbLGOMr (ORCPT ); Mon, 7 Dec 2015 09:12:47 -0500 Date: Mon, 7 Dec 2015 15:12:42 +0100 From: Peter Zijlstra To: Arnaldo Carvalho de Melo Cc: Ingo Molnar , vincent.weaver@maine.edu, jolsa@redhat.com, torvalds@linux-foundation.org, eranian@google.com, tglx@linutronix.de, ak@linux.intel.com, linux-kernel@vger.kernel.org, hpa@zytor.com, linux-tip-commits@vger.kernel.org Subject: Re: [tip:perf/core] perf/x86: Use INST_RETIRED.PREC_DIST for cycles: ppp Message-ID: <20151207141242.GA6357@twins.programming.kicks-ass.net> References: <1448929689-13771-2-git-send-email-andi@firstfloor.org> <20151206131102.GA12167@gmail.com> <20151206220651.GM17308@twins.programming.kicks-ass.net> <20151207064841.GA29761@gmail.com> <20151207140257.GA5851@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151207140257.GA5851@kernel.org> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 07, 2015 at 11:02:58AM -0300, Arnaldo Carvalho de Melo wrote: > Em Mon, Dec 07, 2015 at 07:48:41AM +0100, Ingo Molnar escreveu: > > * Peter Zijlstra wrote: > > > On Sun, Dec 06, 2015 at 02:11:02PM +0100, Ingo Molnar wrote: > > > > Also, I'm not convinced we need a new 'ppp' qualifier for any of this, why not > > > > just replace 'pp' with this event - 'pp' is meant to be our most precise > > > > event. > > > > I requested this because the PREC_DIST events can only be scheduled on a single > > > counter, whereas the existing :pp events can be had on all 4. > > > > This mean you can have 2 concurrent :pp users (without RR), but not :ppp. > > > Ok. Will tooling do the right thing? I.e. will the first user of 'perf top' get > > :ppp automatically, while the second one falls back to :pp? > > I guess so: > > void perf_event_attr__set_max_precise_ip(struct perf_event_attr *attr) > { > attr->precise_ip = 3; Indeed so, I've since confirmed it does also works in practise.