From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752385AbbIAVdd (ORCPT ); Tue, 1 Sep 2015 17:33:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39637 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751256AbbIAVdc (ORCPT ); Tue, 1 Sep 2015 17:33:32 -0400 Date: Tue, 1 Sep 2015 18:33:28 -0300 From: Arnaldo Carvalho de Melo To: pi3orama Cc: Wang Nan , He Kuang , "mingo@kernel.org" , "ast@plumgrid.com" , "linux-kernel@vger.kernel.org" , "lizefan@huawei.com" , Brendan Gregg , Daniel Borkmann , David Ahern , Jiri Olsa , Kaixu Xia , Masami Hiramatsu , Namhyung Kim , Paul Mackerras , Peter Zijlstra Subject: Re: [PATCH 27/31] perf record: Support custom vmlinux path Message-ID: <20150901213328.GH22331@redhat.com> References: <1440822125-52691-1-git-send-email-wangnan0@huawei.com> <1440822125-52691-28-git-send-email-wangnan0@huawei.com> <20150901201917.GF22331@redhat.com> <20150901202126.GG22331@redhat.com> <05D0B732-0100-4C45-8C78-0D5B445C0FFC@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <05D0B732-0100-4C45-8C78-0D5B445C0FFC@163.com> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.20 (2009-12-10) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Wed, Sep 02, 2015 at 05:00:39AM +0800, pi3orama escreveu: > 发自我的 iPhone > > 在 2015年9月2日，上午4:21，Arnaldo Carvalho de Melo 写道： > > Em Tue, Sep 01, 2015 at 05:19:17PM -0300, Arnaldo Carvalho de Melo escreveu: > >> Em Sat, Aug 29, 2015 at 04:22:01AM +0000, Wang Nan escreveu: > >>> From: He Kuang > >>> Make perf-record command support --vmlinux option if BPF_PROLOGUE is on. > >> Ok, this should be supported, i.e. letting the user specify a vmlinux > >> path to use. > >> But it shouldn't be _required_, i.e. we have things like vmlinux_path to > >> try to find it in well known places. > >> Right now it will search for it in the process of trying to load its > >> symtab, but I think we should have a function that tries to find a > >> vmlinux that matches the build-id of the running kernel, for things that > >> want to have access directly to the ELF file with debuginfo without > >> having to load the symtab in a struct dso, etc. > >> I'll look at the next patches to check how you make use of this info... > > > > So, the do it all from 'perf record' is in not yet in this patchkit, > > right? At least not in [ N/31 ] with N > 27, can you point me to it? > It is for patch 8/31, which create kprobe points using add_perf_probe_events(). > > Before this patch it won't search debug info, prevent us use argument like this: > > SEC("lock_page=lock_page page->flags") > > or probe at line number, expect it finds a valid vmlinux from the default path. Argh, that is because init_symbol_maps() uses symbol__init() that is also being used in 'perf record' by now... I.e. it was designed to be called just once, at tool start :-\ Will have to get my head around how this is being used to try to untangle this mess... - Arnaldo