From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754082Ab2DNKV6 (ORCPT ); Sat, 14 Apr 2012 06:21:58 -0400 Received: from merlin.infradead.org ([205.233.59.134]:34272 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752647Ab2DNKV5 convert rfc822-to-8bit (ORCPT ); Sat, 14 Apr 2012 06:21:57 -0400 Message-ID: <1334398906.2528.49.camel@twins> Subject: Re: [PATCH 06/12] perf/x86-ibs: Precise event sampling with IBS for AMD CPUs From: Peter Zijlstra To: Robert Richter Cc: Ingo Molnar , Stephane Eranian , Arnaldo Carvalho de Melo , LKML Date: Sat, 14 Apr 2012 12:21:46 +0200 In-Reply-To: <1333390758-10893-7-git-send-email-robert.richter@amd.com> References: <1333390758-10893-1-git-send-email-robert.richter@amd.com> <1333390758-10893-7-git-send-email-robert.richter@amd.com> 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 Mon, 2012-04-02 at 20:19 +0200, Robert Richter wrote: > + * We map IBS sampling to following precise levels: > + * > + * 1: RIP taken from IBS sample or (if invalid) from stack > + * 2: RIP always taken from IBS sample, samples with an invalid rip > + * are dropped. Thus samples of an event containing two precise > + * modifiers (e.g. r076:pp) only contain (precise) addresses > + * detected with IBS. /* * precise_ip: * * 0 - SAMPLE_IP can have arbitrary skid * 1 - SAMPLE_IP must have constant skid * 2 - SAMPLE_IP requested to have 0 skid * 3 - SAMPLE_IP must have 0 skid * * See also PERF_RECORD_MISC_EXACT_IP */ your 1 doesn't have constant skid. I would suggest only supporting 2 and letting userspace drop !PERF_RECORD_MISC_EXACT_IP records if so desired. That said, mixing the IBS pmu into the regular core pmu isn't exactly pretty..