From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mauro Andreolini Subject: Re: Two questions on perf dwarf callchains Date: Sat, 18 Jan 2014 00:37:32 +0100 Message-ID: <1390001852.8555.8.camel@nb-andreolini> References: <1389954083.1125.23.camel@nb-andreolini.mat.unimo.it> <87d2jq1i7q.fsf@tassilo.jf.intel.com> Reply-To: mauro.andreolini@gmail.com Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-ea0-f178.google.com ([209.85.215.178]:42415 "EHLO mail-ea0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753115AbaAQXhi (ORCPT ); Fri, 17 Jan 2014 18:37:38 -0500 Received: by mail-ea0-f178.google.com with SMTP id a15so880927eae.23 for ; Fri, 17 Jan 2014 15:37:35 -0800 (PST) In-Reply-To: <87d2jq1i7q.fsf@tassilo.jf.intel.com> Sender: linux-perf-users-owner@vger.kernel.org List-ID: To: Andi Kleen Cc: linux-perf-users@vger.kernel.org Il giorno ven, 17/01/2014 alle 12.11 -0800, Andi Kleen ha scritto: > Mauro Andreolini writes: > > file to get perf report to print the function names. > > Is this expected behaviour? How do I get perf to automatically extract > > symbols from compressed files? > > Someone would need to write the code to do that I guess. OK. > > > > To which function would 0x7facc1df12a0 match? It does not even seem to > > be in the mapped address space of "ls". I am clueless. > > The unwinder got confused. A common cause is incomplete or partially > broken dwarf unwind information. May be a compiler problem. Thanks for your time. Right now I am using gcc 4.8.2 20131219 (prerelease) and libunwind 1.1. I noticed the following compile flags: "-O2 -g -fvar-tracking-assignments". I thought that maybe optimizations like function inlining and the like would not play together with debugging info, so I changed them to "-Og -g3 -fvar-tracking-assignments" and recompiled anything, albeit with no luck. I must be missing something big here. How can I be sure to give correct dwarf unwind information? Mauro