From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 24C63C43331 for ; Thu, 26 Mar 2020 21:32:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F1AE82074D for ; Thu, 26 Mar 2020 21:32:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727443AbgCZVcf (ORCPT ); Thu, 26 Mar 2020 17:32:35 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:26658 "EHLO mx0b-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726067AbgCZVce (ORCPT ); Thu, 26 Mar 2020 17:32:34 -0400 Received: from pps.filterd (m0127361.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 02QL3v7a181169; Thu, 26 Mar 2020 17:32:30 -0400 Received: from ppma01wdc.us.ibm.com (fd.55.37a9.ip4.static.sl-reverse.com [169.55.85.253]) by mx0a-001b2d01.pphosted.com with ESMTP id 2ywdr90yjw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 26 Mar 2020 17:32:30 -0400 Received: from pps.filterd (ppma01wdc.us.ibm.com [127.0.0.1]) by ppma01wdc.us.ibm.com (8.16.0.27/8.16.0.27) with SMTP id 02QLVPni022673; Thu, 26 Mar 2020 21:32:29 GMT Received: from b03cxnp08027.gho.boulder.ibm.com (b03cxnp08027.gho.boulder.ibm.com [9.17.130.19]) by ppma01wdc.us.ibm.com with ESMTP id 2ywawn4v62-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 26 Mar 2020 21:32:29 +0000 Received: from b03ledav005.gho.boulder.ibm.com (b03ledav005.gho.boulder.ibm.com [9.17.130.236]) by b03cxnp08027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 02QLWSAf52953524 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 26 Mar 2020 21:32:28 GMT Received: from b03ledav005.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 841BBBE059; Thu, 26 Mar 2020 21:32:28 +0000 (GMT) Received: from b03ledav005.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C85E6BE056; Thu, 26 Mar 2020 21:32:27 +0000 (GMT) Received: from oc3272150783.ibm.com (unknown [9.160.84.73]) by b03ledav005.gho.boulder.ibm.com (Postfix) with ESMTPS; Thu, 26 Mar 2020 21:32:27 +0000 (GMT) Subject: Re: [PATCH] perf tools: update docs regarding kernel/user space unwinding To: Tony Jones , linux-perf-users@vger.kernel.org Cc: Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org References: <20200325164053.10177-1-tonyj@suse.de> From: Paul Clarke Message-ID: <38ba2caa-dadd-52c4-c6ea-5e01b7e59ee2@us.ibm.com> Date: Thu, 26 Mar 2020 16:32:26 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200325164053.10177-1-tonyj@suse.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.645 definitions=2020-03-26_12:2020-03-26,2020-03-26 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 bulkscore=0 adultscore=0 impostorscore=0 lowpriorityscore=0 phishscore=0 priorityscore=1501 clxscore=1011 suspectscore=0 mlxlogscore=962 mlxscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2003260148 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/25/20 11:40 AM, Tony Jones wrote: > The method of unwinding for kernel space is defined by the kernel config, > not by the value of --call-graph. Improve the documentation to reflect > this. > diff --git a/tools/perf/Documentation/perf-config.txt b/tools/perf/Documentation/perf-config.txt > index 8ead55593984..88cf35fbedc5 100644 > --- a/tools/perf/Documentation/perf-config.txt > +++ b/tools/perf/Documentation/perf-config.txt > @@ -405,14 +405,16 @@ ui.*:: > This option is only applied to TUI. > > call-graph.*:: > - When sub-commands 'top' and 'report' work with -g/—-children > - there're options in control of call-graph. > + The following controls the handling of call-graphs (obtained via the > + -g/--callgraph options). > > call-graph.record-mode:: > - The record-mode can be 'fp' (frame pointer), 'dwarf' and 'lbr'. > - The value of 'dwarf' is effective only if perf detect needed library > - (libunwind or a recent version of libdw). > - 'lbr' only work for cpus that support it. > + The mode for user space can be 'fp' (frame pointer), 'dwarf' > + and 'lbr'. The value 'dwarf' is effective only if libunwind > + (or a recent version of libdw) is present on the system; > + the value 'lbr' only works for certain cpus. The method for > + kernel space is controlled not by this option but by the > + kernel config (CONFIG_UNWINDER_*). Your changes are just copying the old text, so this isn't a criticism of your patches. Do we have information to replace "a recent version of libdw", which will quickly get stale? PC