From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751916AbbE0Iv2 (ORCPT ); Wed, 27 May 2015 04:51:28 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:35188 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750977AbbE0IvY (ORCPT ); Wed, 27 May 2015 04:51:24 -0400 Date: Wed, 27 May 2015 10:51:13 +0200 From: Peter Zijlstra To: Will Deacon Cc: Mark Rutland , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "acme@kernel.org" , Liviu Dudau , Lorenzo Pieralisi , "mingo@redhat.com" , "paulus@samba.org" , Sudeep Holla , Drew Richardson Subject: Re: [PATCH 1/7] perf: allow for PMU-specific event filtering Message-ID: <20150527085113.GV3644@twins.programming.kicks-ass.net> References: <1431533549-27715-1-git-send-email-mark.rutland@arm.com> <1431533549-27715-2-git-send-email-mark.rutland@arm.com> <20150522140844.GA1619@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150522140844.GA1619@arm.com> 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 Fri, May 22, 2015 at 03:08:44PM +0100, Will Deacon wrote: > Hi Mark, > > On Wed, May 13, 2015 at 05:12:23PM +0100, Mark Rutland wrote: > > In certain circumstances it may not be possible to schedule particular > > events due to constraints other than a lack of hardware counters (e.g. > > on big.LITTLE systems where CPUs support different events). The core > > perf event code does not distinguish these cases and pessimistically > > assumes that any failure to schedule an event means that it is not worth > > attempting to schedule later events, even if some hardware counters are > > still unused. > > > > When an event a pmu cannot schedule exists in a flexible group list it > > can unnecessarily prevent event groups following it in the list from > > being scheduled (until it is rotated to the end of the list). This means > > some events are scheduled for only a portion of the time they could be, > > and for short running programs no events may be scheduled if the list is > > initially sorted in an unfortunate order. > > > > This patch adds a new (optional) filter_match function pointer to struct > > pmu which a pmu driver can use to tell perf core when an event matches > > pmu-specific scheduling requirements. This plugs into the existing > > event_filter_match logic, and makes it possible to avoid the scheduling > > problem described above. When no filter is provided by the PMU, the > > existing behaviour is retained. > > > > Signed-off-by: Mark Rutland > > Acked-by: Will Deacon > > Cc: Peter Zijlstra > > Cc: Paul Mackerras > > Cc: Ingo Molnar > > Cc: Arnaldo Carvalho de Melo > > --- > > include/linux/perf_event.h | 5 +++++ > > kernel/events/core.c | 8 +++++++- > > 2 files changed, 12 insertions(+), 1 deletion(-) > > Whilst I'm really keen to merge the architecture-specific parts of this > series, I'm going to need an Ack from one of the perf core maintainers > on this patch. > > Peter, can you take a look please? (and I assume this is self-contained > enough not to conflict heavily with the current perf queue?). Acked-by: Peter Zijlstra (Intel) Merge it however you like, but test merge against tip/perf/core or something of that nature, if a conflict pops up, maybe keep this one patch in a separate branch such that it can also be pulled into tip/perf/core -- but as you say, I don't really suspect a conflict.