Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752288AbZFVOyV (ORCPT ); Mon, 22 Jun 2009 10:54:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751233AbZFVOyM (ORCPT ); Mon, 22 Jun 2009 10:54:12 -0400 Received: from mail-fx0-f224.google.com ([209.85.220.224]:36430 "EHLO mail-fx0-f224.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750936AbZFVOyL (ORCPT ); Mon, 22 Jun 2009 10:54:11 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=mime-version:reply-to:in-reply-to:references:date:message-id :subject:from:to:cc:content-type:content-transfer-encoding; b=XP5H7ZzhV+9bOSB1nppgU5xV7yi2PGkssPHAC8YgU1GwQ7UmKg2LlbQNfViLCf9reb 7i1bHS5OgOr9bbBFsXQ7FuYj0yZiCAdK1DczdWTR1bG5chxkjwBDK29tTeDQc5bJoQ3P JcIl2e4W+n8FISvpkf0X6Uvi7XtFgWZz/Tqp0= MIME-Version: 1.0 Reply-To: eranian@gmail.com In-Reply-To: <20090622115627.GL24366@elte.hu> References: <7c86c4470906161042p7fefdb59y10f8ef4275793f0e@mail.gmail.com> <20090622115627.GL24366@elte.hu> Date: Mon, 22 Jun 2009 16:54:13 +0200 Message-ID: <7c86c4470906220754yccebd67r4d87ff85af5c6f2e@mail.gmail.com> Subject: Re: I.11 - Missing definitions for generic events From: stephane eranian To: Ingo Molnar Cc: LKML , Andrew Morton , Thomas Gleixner , Robert Richter , Peter Zijlstra , Paul Mackerras , Andi Kleen , Maynard Johnson , Carl Love , Corey J Ashford , Philip Mucci , Dan Terpstra , perfmon2-devel Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1482 Lines: 36 On Mon, Jun 22, 2009 at 1:56 PM, Ingo Molnar wrote: >> 11/ Missing definitions for generic hardware events >> >> As soon as you define generic events, you need to provide a clear >> and precise definition at to what they measure. This is crucial to >> make them useful. I have not seen such a definition yet. > > Do you mean their names aren't clear enough? :-) > No I'd like to see a defintion behind every name: PERF_COUNT_HW_CPU_CYCLES: impacted by freq scaling or not? PERF_COUNT_HW_INSTRUCTIONS PERF_COUNT_HW_CACHE_REFERENCES: what cache level, data, code? PERF_COUNT_HW_CACHE_MISSES: what cache level, data, code? PERF_COUNT_HW_BRANCH_INSTRUCTIONS: taken, not-taken? PERF_COUNT_HW_BRANCH_MISSES PERF_COUNT_HW_BUS_CYCLES: what bus? Take BUS_CYCLES, and based on my example on Core with UNHALTED_REFERENCE_CYCLE, without a clear definition, it seems hard to understand if you need to map it to 0x13c on a generic counter or on fixed counter 2. Having clearly spelled out definitions help port PCL to other processors, it also helps user understand which event they need to select. Users should not have to dig through the code to find the actual mapping for each PMU to understand what the events actually measure. -- 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/