From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753288AbdKHU4u (ORCPT ); Wed, 8 Nov 2017 15:56:50 -0500 Received: from mga07.intel.com ([134.134.136.100]:50959 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753274AbdKHU4q (ORCPT ); Wed, 8 Nov 2017 15:56:46 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.44,365,1505804400"; d="scan'208";a="1241678033" Date: Wed, 8 Nov 2017 12:56:43 -0800 From: Andi Kleen To: Stephane Eranian Cc: linux-kernel@vger.kernel.org, acme@redhat.com, peterz@infradead.org, mingo@elte.hu, kan.liang@intel.com, jolsa@redhat.com Subject: Re: [PATCH v3 4/5] perf/record: add documentation for sampling skid ip Message-ID: <20171108205643.GB8522@tassilo.jf.intel.com> References: <1510127797-22483-1-git-send-email-eranian@google.com> <1510127797-22483-5-git-send-email-eranian@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1510127797-22483-5-git-send-email-eranian@google.com> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt > index 5a626ef666c2..3b156fa03c99 100644 > --- a/tools/perf/Documentation/perf-record.txt > +++ b/tools/perf/Documentation/perf-record.txt > @@ -57,6 +57,14 @@ OPTIONS > FP mode, "dwarf" for DWARF mode, "lbr" for LBR mode and > "no" for disable callgraph. > - 'stack-size': user stack size for dwarf mode > + - 'skid_ip' : boolean, captures the unmodified interrupt instruction pointer > + (IP) in each sample. Usually with event-based sampling, the IP > + has skid and rarely point to the instruction which caused the > + event to overflow. On some architectures, the hardware can eliminate > + the skid and perf_events returns it as the IP with precise sampling is > + enabled. But for certain measurements, it may be useful to have both > + the correct and skid ip. This option enable capturing the skid ip in > + additional to the corrected ip. Default is: false Actually in the scanner you use 'skid-ip' (with minus). Documentation should at least match the scanner. _ is usually safer than - -Andi