From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753201AbeCPKby (ORCPT ); Fri, 16 Mar 2018 06:31:54 -0400 Received: from merlin.infradead.org ([205.233.59.134]:38526 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752733AbeCPKbw (ORCPT ); Fri, 16 Mar 2018 06:31:52 -0400 Date: Fri, 16 Mar 2018 11:31:29 +0100 From: Peter Zijlstra To: Alexey Budankov Cc: tglx@linutronix.de, Dmitry.Prohorov@intel.com, alexander.shishkin@linux.intel.com, acme@redhat.com, mark.rutland@arm.com, linux-kernel@vger.kernel.org, hpa@zytor.com, jolsa@redhat.com, torvalds@linux-foundation.org, mingo@kernel.org, vincent.weaver@maine.edu, kan.liang@intel.com, eranian@google.com, davidcc@google.com, valery.cherepennikov@intel.com, linux-tip-commits@vger.kernel.org Subject: Re: [PATCH] perf: Fix sibling iteration Message-ID: <20180316103129.GC4064@hirez.programming.kicks-ass.net> References: <20180315170129.GX4043@hirez.programming.kicks-ass.net> <0be54adb-a7be-cd2f-dfcb-4166dfe432ea@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0be54adb-a7be-cd2f-dfcb-4166dfe432ea@linux.intel.com> User-Agent: Mutt/1.9.3 (2018-01-21) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 16, 2018 at 12:59:34PM +0300, Alexey Budankov wrote: > Hi, > On 15.03.2018 20:01, Peter Zijlstra wrote: > > Subject: perf: Fix sibling iteration > > From: Peter Zijlstra > > Date: Thu Mar 15 17:36:56 CET 2018 > > > > Mark noticed that the change to sibling_list changed some iteration > > semantics; because previously we used group_list as list entry, > > sibling events would always have an empty sibling_list. > > > > But because we now use sibling_list for both list head and list entry, > > siblings will report as having siblings. > > > > Fix this with a custom for_each_sibling_event() iterator. > > > > Suggested-by: Mark Rutland > > Reported-by: Mark Rutland > > Fixes: 8343aae66167 ("perf/core: Remove perf_event::group_entry") > > Signed-off-by: Peter Zijlstra (Intel) > > --- > > Applied to tip repo and run testing on Fedora 27/x86_64 (client skylake 8 cores): There is at least one more known issue with that patch, but neither Mark nor me could reproduce so far, so we don't know if we're right about the cause.