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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_MUTT 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 93232C004C9 for ; Mon, 29 Apr 2019 08:45:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6D28F2063F for ; Mon, 29 Apr 2019 08:45:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727687AbfD2Ipz (ORCPT ); Mon, 29 Apr 2019 04:45:55 -0400 Received: from smtp2200-217.mail.aliyun.com ([121.197.200.217]:33320 "EHLO smtp2200-217.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727480AbfD2Ipz (ORCPT ); Mon, 29 Apr 2019 04:45:55 -0400 X-Alimail-AntiSpam: AC=CONTINUE;BC=0.2451035|-1;CH=green;DM=CONTINUE|CONTINUE|true|0.145498-0.00694801-0.847554;FP=0|0|0|0|0|-1|-1|-1;HT=e01a16368;MF=han_mao@c-sky.com;NM=1;PH=DS;RN=4;RT=4;SR=0;TI=SMTPD_---.ERaVMaQ_1556527548; Received: from localhost(mailfrom:han_mao@c-sky.com fp:SMTPD_---.ERaVMaQ_1556527548) by smtp.aliyun-inc.com(10.147.41.137); Mon, 29 Apr 2019 16:45:49 +0800 Date: Mon, 29 Apr 2019 16:45:00 +0800 From: Mao Han To: Palmer Dabbelt Cc: linux-riscv@lists.infradead.org, guoren@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] riscv: Add support for libdw Message-ID: <20190429084441.GC22718@vmh-VirtualBox> References: <99f15d5c74727c31bf8d08b6cf948754e3e09943.1554961908.git.han_mao@c-sky.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 25, 2019 at 02:11:04PM -0700, Palmer Dabbelt wrote: > On Thu, 11 Apr 2019 00:53:50 PDT (-0700), han_mao@c-sky.com wrote: > >This patch add support for DWARF register mappings and libdw registers > >initialization, which is used by perf callchain analyzing when > >--call-graph=dwarf is given. > > Is there any way to make this the only backtracer? It's the only one that's > likely to be useful on RISC-V without recompiling everything with > -fno-omit-frame-pointer, which has a major performance hit. > Frame pointer is the default record mode in record_callchain_opt. Some generic modification seems required to change this, default to use dwarf if riscv and show corresponding message in --help. Thanks, Mao Han