From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752035AbcEDNqr (ORCPT ); Wed, 4 May 2016 09:46:47 -0400 Received: from foss.arm.com ([217.140.101.70]:45385 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751344AbcEDNqo (ORCPT ); Wed, 4 May 2016 09:46:44 -0400 Date: Wed, 4 May 2016 14:46:42 +0100 From: Will Deacon To: Mark Rutland Cc: Peter Zijlstra , Catalin Marinas , Ingo Molnar , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] perf/core / arm_pmu: special-case hetereogeneous CPUs Message-ID: <20160504134641.GB31744@arm.com> References: <20160425175837.GB3141@leverpostej> <20160425190334.GK3448@twins.programming.kicks-ass.net> <20160426103346.GA20836@leverpostej> <20160504134419.GA15849@leverpostej> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160504134419.GA15849@leverpostej> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 04, 2016 at 02:44:20PM +0100, Mark Rutland wrote: > Hi, > > On Tue, Apr 26, 2016 at 11:33:46AM +0100, Mark Rutland wrote: > > On Mon, Apr 25, 2016 at 09:03:34PM +0200, Peter Zijlstra wrote: > > > On Mon, Apr 25, 2016 at 06:58:37PM +0100, Mark Rutland wrote: > > > > Hi, > > > > > > > > When booting an arm64 defconfig linux-next (next-20160422) on an ARM > > > > Juno system, I hit a WARN_ON_ONCE in perf_pmu_register (see backtrace at > > > > the end of this email). > > > > > > > > This was introduced by commit 26657848502b7847 ("perf/core: Verify we > > > > have a single perf_hw_context PMU") where we forcefully prevent multiple > > > > PMUs from sharing perf_hw_context (with a warning), and force additional > > > > PMUs to use perf_invalid_context. > > > > > > Are you happy to revert 26657848502b787 for the timebeing? Or to somehow > > > > predicate the check such that it doesn't adversely affect those HW PMUs? > > > > > > I'm happy with a chicken bit for now, its already found two real issues, > > > so I'd like to keep it. > > > > Ok, how about the below? (based on next-20160422). > > Peter, any thoughts? > > This is still an issue for us in next-20160504 (to which the patch still > applies). > > Will, I assume that you're ok with the change to drivers/perf/arm_pmu.c. Yes, they're pretty straighforward. Will