From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758155Ab2C1K62 (ORCPT ); Wed, 28 Mar 2012 06:58:28 -0400 Received: from merlin.infradead.org ([205.233.59.134]:55676 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757857Ab2C1K60 convert rfc822-to-8bit (ORCPT ); Wed, 28 Mar 2012 06:58:26 -0400 Message-ID: <1332932290.2528.22.camel@twins> Subject: Re: [RFC PATCH 0/5] perf: Intel uncore pmu counting support From: Peter Zijlstra To: Andi Kleen Cc: Ingo Molnar , "Yan, Zheng" , mingo@elte.hu, eranian@google.com, linux-kernel@vger.kernel.org, ming.m.lin@intel.com Date: Wed, 28 Mar 2012 12:58:10 +0200 In-Reply-To: <20120328085732.GV22197@one.firstfloor.org> References: <1332916998-10628-1-git-send-email-zheng.z.yan@intel.com> <20120328064928.GA21725@gmail.com> <20120328085732.GV22197@one.firstfloor.org> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2012-03-28 at 10:57 +0200, Andi Kleen wrote: > The main problem is that we don't know currently what events are > really useful. People need to play around with the raw events > first to find that out. But to do that really already need some > in tree support because out of tree is too painful to use: it's > a chicken and egg problem. So you're saying Intel just made the hardware without any idea if it was useful or not? Somehow that seems rather unlikely. It seems to me they had at least one but very likely several strong use-cases before they designed the hardware. What Ingo is asking is to implement these, so that everybody can enjoy them instead of being a conduit for Intel proprietary tools. A minimal driver with no users except $$ tools is not acceptable.