Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751598AbaKKNUO (ORCPT ); Tue, 11 Nov 2014 08:20:14 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:48048 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751164AbaKKNUM (ORCPT ); Tue, 11 Nov 2014 08:20:12 -0500 Date: Tue, 11 Nov 2014 14:20:00 +0100 From: Peter Zijlstra To: Alexander Shishkin Cc: Ingo Molnar , linux-kernel@vger.kernel.org, Robert Richter , Frederic Weisbecker , Mike Galbraith , Paul Mackerras , Stephane Eranian , Andi Kleen , kan.liang@intel.com, adrian.hunter@intel.com, acme@infradead.org Subject: Re: [PATCH v5 12/20] x86: perf: intel_pt: Intel PT PMU driver Message-ID: <20141111132000.GM10501@worktop.programming.kicks-ass.net> References: <1413207948-28202-1-git-send-email-alexander.shishkin@linux.intel.com> <1413207948-28202-13-git-send-email-alexander.shishkin@linux.intel.com> <20141022143241.GT12706@worktop.programming.kicks-ass.net> <8738a4crgg.fsf@ashishki-desk.ger.corp.intel.com> <20141104155734.GL12706@worktop.programming.kicks-ass.net> <87wq72asjo.fsf@ashishki-desk.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87wq72asjo.fsf@ashishki-desk.ger.corp.intel.com> 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 Tue, Nov 11, 2014 at 01:24:43PM +0200, Alexander Shishkin wrote: > Peter Zijlstra writes: > > Now I'm not sure we want to export all the bits you're using though. > > Like the topa_multiple_entires, that appears an implementation detail > > userspace should not really care about either way. > > Actually, userspace can make assumptions about lost data from this > bit. Do explain; it feels entirely wrong to expose something like this, esp. since this crappy single TOPA thing is going away. > But there are others, such as encoded address length. In future > there will also be several "caps" with allowed values for certain bit > fields in RTIT_CTL, such as timing packet frequencies. No, those should not be caps, those should be in the format description. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/