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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 23203C4332B for ; Mon, 23 Mar 2020 10:03:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F3630206F8 for ; Mon, 23 Mar 2020 10:03:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727804AbgCWKD3 (ORCPT ); Mon, 23 Mar 2020 06:03:29 -0400 Received: from mail.ut.ac.ir ([80.66.177.10]:37792 "EHLO mail.ut.ac.ir" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727788AbgCWKD3 (ORCPT ); Mon, 23 Mar 2020 06:03:29 -0400 Received: from localhost (localhost [127.0.0.1]) by mail.ut.ac.ir (Postfix) with ESMTP id AE2011DAADF; Mon, 23 Mar 2020 14:33:26 +0430 (+0430) Received: from mail.ut.ac.ir ([127.0.0.1]) by localhost (mail.ut.ac.ir [127.0.0.1]) (amavisd-new, port 10024) with LMTP id Z2L6xYnkygeB; Mon, 23 Mar 2020 14:33:24 +0430 (+0430) Received: from mail.ut.ac.ir (mail.ut.ac.ir [194.225.0.10]) by mail.ut.ac.ir (Postfix) with ESMTP id 8BFEF1DAACC; Mon, 23 Mar 2020 14:33:24 +0430 (+0430) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Mon, 23 Mar 2020 14:33:24 +0430 From: ahmadkhorrami To: Jiri Olsa Cc: Steven Rostedt , Linux-trace Users , Arnaldo Carvalho de Melo , Peter Zijlstra , linux-trace-users-owner@vger.kernel.org, Jin Yao Subject: Re: Re: Wrong Perf Backtraces In-Reply-To: <20200323084942.GA1534489@krava> References: <157597d74ff17f781d9de7e7e3defd13@ut.ac.ir> <20200322203421.715b32d8@oasis.local.home> <21b3df4080709f193d62b159887e2a83@ut.ac.ir> <20200323084942.GA1534489@krava> Message-ID: X-Sender: ahmadkhorrami@ut.ac.ir User-Agent: Roundcube Webmail/1.3.6 Sender: linux-trace-users-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-users@vger.kernel.org Archived-At: List-Archive: List-Post: Hi, It seems that my previous e-mail is not sent, properly. So, here is a link to the stackoverflow question: https://stackoverflow.com/questions/60766026/wrong-perf-backtraces The perf is for Ubuntu 18.04 with the following "uname -a" output: Linux Ahmad-Laptop 5.0.0-37-generic #40~18.04.1-Ubuntu SMP Thu Nov 14 12:06:39 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux I also used a compiled Linux-5.4.7 kernel and its corresponding Perf tool. Regards. On 2020-03-23 13:19, Jiri Olsa wrote: > On Mon, Mar 23, 2020 at 07:48:26AM +0430, ahmadkhorrami wrote: > >> Here is a link to the detailed question at Stackoverflow: >> >> https://stackoverflow.com/questions/60766026/wrong-perf-backtraces > > hi, > what perf version are you running? > > jirka > > I can copy it here, if needed. > > Thanks > > On 2020-03-23 05:04, Steven Rostedt wrote: > > On Mon, 23 Mar 2020 00:54:01 +0430 > ahmadkhorrami wrote: > > Hi, > I used "Perf" to extract call graphs in an evince benchmark. The > command > used is as follows: > sudo perf record -d --call-graph dwarf -c 10000 e > mem_load_uops_retired.l3_miss:uppp /opt/evince-3.28.4/bin/evince > > I extracted the backtraces using "perf script" and found out that there > are many corrupted backtrace instances. Some contained repeated > function > calls, for example two consecutive gmallocn()s exactly at the same > offsets. There are also some backtraces where the callers and callees > do > not match. > Could you show some examples of the backtraces you mention? > > Note that that mappings are correct. In other words, each single line > of > the reported backtraces is correct (i.e., addresses match with > functions). But is seems that there are some function calls in the > middle, which are missed by "Perf". Strangely, in all runs (and also > with different sampling frequencies) the problem occurs exactly at the > same place. > > I am really confused and looking forward to any help. I can also send > backtraces if needed. > -- Steve