From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752655AbdESMg4 (ORCPT ); Fri, 19 May 2017 08:36:56 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:49522 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750728AbdESMgz (ORCPT ); Fri, 19 May 2017 08:36:55 -0400 Date: Fri, 19 May 2017 14:36:48 +0200 From: Peter Zijlstra To: "Jin, Yao" Cc: acme@kernel.org, jolsa@kernel.org, mingo@redhat.com, alexander.shishkin@linux.intel.com, Linux-kernel@vger.kernel.org, ak@linux.intel.com, kan.liang@intel.com, yao.jin@intel.com, Will Deacon , Mark Rutland Subject: Re: [PATCH] perf/x86/intel: Drop kernel samples even though :u is specified Message-ID: <20170519123648.p4tkt6xrt5xachuw@hirez.programming.kicks-ass.net> References: <1495189152-5766-1-git-send-email-yao.jin@linux.intel.com> <20170519092905.yivnfjyhblm5wiap@hirez.programming.kicks-ass.net> <20170519121056.c45jbsfgcdjfuoow@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 19, 2017 at 08:24:19PM +0800, Jin, Yao wrote: > > Ah, I was more thinking of something like PERF_PMU_CAP_NO_SKID or > > something that would skip the test and preserve current behaviour. > > OK, I understand now. For example, for PEBS event, its capabilities should > be set with PERF_PMU_CAP_NO_SKID. Except you cannot in fact do that, since PEBS is the same struct pmu as the normal counters (they share counter space after all). Also, weren't there PEBS errata that would allow this to happen? But no, more for other architectures to opt out for some reason. But I'm thinking we want to start out by unconditionally doing this. It would be good to try and Cc most arch pmu maintainers on this though, so they can object.