From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752606AbaJBImR (ORCPT ); Thu, 2 Oct 2014 04:42:17 -0400 Received: from casper.infradead.org ([85.118.1.10]:55276 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752016AbaJBIlc (ORCPT ); Thu, 2 Oct 2014 04:41:32 -0400 Date: Thu, 2 Oct 2014 10:41:25 +0200 From: Peter Zijlstra To: Matt Fleming Cc: Andi Kleen , Ingo Molnar , Jiri Olsa , Arnaldo Carvalho de Melo , Thomas Gleixner , linux-kernel@vger.kernel.org, "H. Peter Anvin" , Matt Fleming Subject: Re: [PATCH v2 00/11] perf: Intel Cache QoS Monitoring support Message-ID: <20141002084125.GB3003@worktop.programming.kicks-ass.net> References: <1412174192-7010-1-git-send-email-matt@console-pimps.org> <8738b7eac2.fsf@tassilo.jf.intel.com> <20141002065124.GF14343@console-pimps.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141002065124.GF14343@console-pimps.org> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 02, 2014 at 07:51:24AM +0100, Matt Fleming wrote: > On Wed, 01 Oct, at 02:42:05PM, Andi Kleen wrote: > > Matt Fleming writes: > > > > > > Changes in v2: > > > > > > - Added Jiri Olsa's Acked-by to PATCH 02/11. > > > > > > - Use x86_match_cpu() in intel_cqm_init() and make sure we grab the > > > hotplug lock to prevent races as pointed out by Andi Kleen in > > > PATCH 08/11. > > > > > > - Delete a stale comment in commit message of PATCH 10/11. > > > > No support for a modular driver? > > I didn't include support for that because none of the other x86 pmu > drivers are buildable as modules. Is there a reason for that? Not really, the rapl driver could easily be a module, and I think there were osme patches to make the uncore driver a module. > It's not clear to me that it would be a worthwhile change to make this > buildable as a module, since that would require a Kconfig entry and the > user would be required to make a decision regarding whether or not they > want to build CQM support. > > It's much simpler to just build it in and enable it based on > CONFIG_PERF_EVENTS + CONFIG_INTEL_CPU. In fact, that's one of the things > I've always liked about the pmu drivers, if I move to a new machine and > turn on PERF_EVENTS the correct drivers will be run. Some people worry about the memory footprint of all that.. That said, I think we can do without the Kconfig stuff if we allow CONFIG_PERF_EVENTS to be a tristate, in that case M would build everything that can be a module as a module and keep the rest builtin.