Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752483AbdFOQoQ (ORCPT ); Thu, 15 Jun 2017 12:44:16 -0400 Received: from mail-io0-f170.google.com ([209.85.223.170]:36693 "EHLO mail-io0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751623AbdFOQoO (ORCPT ); Thu, 15 Jun 2017 12:44:14 -0400 MIME-Version: 1.0 In-Reply-To: <20170615151018.GA4789@tassilo.jf.intel.com> References: <1497534989-29231-1-git-send-email-eranian@google.com> <20170615151018.GA4789@tassilo.jf.intel.com> From: Stephane Eranian Date: Thu, 15 Jun 2017 09:44:07 -0700 Message-ID: Subject: Re: [PATCH 0/5] perf: add support for capturing skid IP To: Andi Kleen Cc: LKML , Arnaldo Carvalho de Melo , Peter Zijlstra , "mingo@elte.hu" , "Liang, Kan" , Jiri Olsa Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 800 Lines: 17 On Thu, Jun 15, 2017 at 8:10 AM, Andi Kleen wrote: > On Thu, Jun 15, 2017 at 06:56:24AM -0700, Stephane Eranian wrote: >> This patchs adds a new sample record type called >> PERF_SAMPLE_SKID_IP. The goal is to record >> the unmodified interrupted instruction pointer (IP) as seen by >> the kernel and reflected in the machine state. > > Patches look reasonable for me. > > If you only cared about branches it would be more natural to model > it like a 1 entry LBR. That would make a lot more tooling work > automatically. > You'd still have to modify tooling to present correct column headers. It is mostly interesting for branches for sure but any situation where you want to skidless IP and the skid IP would work because they tell you something about the sampled instruction.