Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756590Ab0DNSqO (ORCPT ); Wed, 14 Apr 2010 14:46:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56751 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755243Ab0DNSqM (ORCPT ); Wed, 14 Apr 2010 14:46:12 -0400 Message-ID: <4BC60E3D.40200@redhat.com> Date: Wed, 14 Apr 2010 11:49:33 -0700 From: Masami Hiramatsu User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.7) Gecko/20100120 Fedora/3.0.1-1.fc11 Thunderbird/3.0.1 MIME-Version: 1.0 To: Heiko Carstens CC: Ian Munsie , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, benh@kernel.crashing.org, Peter Zijlstra , Paul Mackerras , Ingo Molnar , Arnaldo Carvalho de Melo , Frederic Weisbecker Subject: Re: [PATCH v2 1/2] perf: Move arch specific code into separate arch directory References: <1271221600-25533-1-git-send-email-imunsie@au.ibm.com> <1271221600-25533-2-git-send-email-imunsie@au.ibm.com> <4BC5D534.8010508@redhat.com> <20100414170008.GA2359@osiris.boeblingen.de.ibm.com> In-Reply-To: <20100414170008.GA2359@osiris.boeblingen.de.ibm.com> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3051 Lines: 66 Heiko Carstens wrote: > On Wed, Apr 14, 2010 at 07:46:12AM -0700, Masami Hiramatsu wrote: >> Ian Munsie wrote: >>> From: Ian Munsie >>> >>> The perf userspace tool included some architecture specific code to map >>> registers from the DWARF register number into the names used by the regs >>> and stack access API. >>> >>> This patch moves the architecture specific code out into a separate >>> arch/x86 directory along with the infrastructure required to use it. >>> >>> Signed-off-by: Ian Munsie >>> --- >>> Changes since v1: From Masami Hiramatsu's suggestion, I added a check in the >>> Makefile for if the arch specific Makefile defines PERF_HAVE_DWARF_REGS, >>> printing a message during build if it has not. This simplifies the code >>> removing the odd macro from the previous version and the need for an arch >>> specific arch_dwarf-regs.h. I have not entirely disabled DWARF support for >>> architectures that don't implement the register mappings, so that they can >>> still add a probe based on a line number (they will be missing the ability to >>> capture the value of a variable from a register). >> >> Hmm, sorry, I don't think it is a good way to go... IMHO, porting dwarf-regs.c >> is so easy (you can just refer systemtap/runtime/loc2c-runtime.h), easier >> than porting kprobe-tracer on another arch. And perf is a part of kernel tree. >> It means that someone who are porting kprobe-tracer, he should port >> dwarf-regs.c too. In that case, PERF_HAVE_DWARF_REGS flag will be used only >> between those two patches in same patchset. So, I suggested you to drop dwarf >> support if dwarf-regs mapping doesn't exist. >> >> AFAIK, at this point, only s390 users are affected. I'd like to ask >> them to just port a register mapping on perf and test it too. > > Hm, I'm a bit lost here. Probably due to lack of context. What would be missing > on s390 and what am I supposed to implement and how can I test it? > Any pointers to git commits? Ah, sorry about that. Now we're talking about an idea about porting perf-probe on some architectures which supports kprobe-tracer. Ian's patch (https://patchwork.kernel.org/patch/92328/) is currently under discussion, so there is no git commit yet (but it will be in a few days). So what I'd like to suggest you is implementing s390 version of DWARF register mapping support(ppc version is here: https://patchwork.kernel.org/patch/92329/) for perf probe (a subcommand of perf tools(tools/perf)) and test the perf-probe can work. For testing, you may need to compile kernel with CONFIG_DEBUG_INFO, install elfutils-devel, and make perf tools (cd tools/perf; make). And then, execute below command. $ ./perf probe -v --add 'vfs_read file' Thank you, -- Masami Hiramatsu e-mail: mhiramat@redhat.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/