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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT 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 5F497C43381 for ; Mon, 18 Feb 2019 13:59:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2CD2A20842 for ; Mon, 18 Feb 2019 13:59:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550498340; bh=+LN0SxZ2nsNjztTM4fp+LrjAK6ddPQnURu9ASxWKcog=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=CwOSGaflJ81LZBtkN3UV91Zz46zMQsZzMIlb8VbewWDyIeDZtSk/nvvo9RuifYwnv e7mnfNVKqQwnVrShS76YpBHEeuowNNSrfJhvKwlf/2Gfia7IjAmdaZAKbJXKt2nYH7 JdHreAMpdnbL9wJwBN39c3EpRECB/YUGe6TPlxKo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388473AbfBRN66 (ORCPT ); Mon, 18 Feb 2019 08:58:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:39590 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388444AbfBRN6u (ORCPT ); Mon, 18 Feb 2019 08:58:50 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 699E620842; Mon, 18 Feb 2019 13:58:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550498328; bh=+LN0SxZ2nsNjztTM4fp+LrjAK6ddPQnURu9ASxWKcog=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fiJvrN19+cluB3ubwn+g1Lth1vB25uPEH8AQOu9NttRcW0yXnbT85URiAKuk64zMx KGkclojERtcp0cW1Ky8F+0If7FxJlL7Y/qT67qrkVSTfBvoe0oUhR9DFnPWAzir/0j e7asuHTD3yg41D3sU+kXnUubITend04OnU3kiNmc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nikson Kanti Paul , Milian Wolff , Jiri Olsa , Namhyung Kim , Arnaldo Carvalho de Melo , Amit Shah , David Woodhouse , Sasha Levin Subject: [PATCH 4.9 34/58] perf report: Include partial stacks unwound with libdw Date: Mon, 18 Feb 2019 14:43:55 +0100 Message-Id: <20190218133511.298067634@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190218133508.567416115@linuxfoundation.org> References: <20190218133508.567416115@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ commit 5ea0416f51cc93436bbe497c62ab49fd9cb245b6 upstream. So far the whole stack was thrown away when any error occurred before the maximum stack depth was unwound. This is actually a very common scenario though. The stacks that got unwound so far are still interesting. This removes a large chunk of differences when comparing perf script output for libunwind and libdw perf unwinding. E.g. with libunwind: ~~~~~ heaptrack_gui 2228 135073.388524: 479408 cycles: ffffffff811749ed perf_iterate_ctx ([kernel.kallsyms]) ffffffff81181662 perf_event_mmap ([kernel.kallsyms]) ffffffff811cf5ed mmap_region ([kernel.kallsyms]) ffffffff811cfe6b do_mmap ([kernel.kallsyms]) ffffffff811b0dca vm_mmap_pgoff ([kernel.kallsyms]) ffffffff811cdb0c sys_mmap_pgoff ([kernel.kallsyms]) ffffffff81033acb sys_mmap ([kernel.kallsyms]) ffffffff81631d37 entry_SYSCALL_64_fastpath ([kernel.kallsyms]) 192ca mmap64 (/usr/lib/ld-2.25.so) 59a9 _dl_map_object_from_fd (/usr/lib/ld-2.25.so) 83d0 _dl_map_object (/usr/lib/ld-2.25.so) cda1 openaux (/usr/lib/ld-2.25.so) 1834f _dl_catch_error (/usr/lib/ld-2.25.so) cfe2 _dl_map_object_deps (/usr/lib/ld-2.25.so) 3481 dl_main (/usr/lib/ld-2.25.so) 17387 _dl_sysdep_start (/usr/lib/ld-2.25.so) 4d37 _dl_start (/usr/lib/ld-2.25.so) d87 _start (/usr/lib/ld-2.25.so) heaptrack_gui 2228 135073.388677: 611329 cycles: 1a3e0 strcmp (/usr/lib/ld-2.25.so) 82b2 _dl_map_object (/usr/lib/ld-2.25.so) cda1 openaux (/usr/lib/ld-2.25.so) 1834f _dl_catch_error (/usr/lib/ld-2.25.so) cfe2 _dl_map_object_deps (/usr/lib/ld-2.25.so) 3481 dl_main (/usr/lib/ld-2.25.so) 17387 _dl_sysdep_start (/usr/lib/ld-2.25.so) 4d37 _dl_start (/usr/lib/ld-2.25.so) d87 _start (/usr/lib/ld-2.25.so) ~~~~~ With libdw without this patch: ~~~~~ heaptrack_gui 2228 135073.388524: 479408 cycles: ffffffff811749ed perf_iterate_ctx ([kernel.kallsyms]) ffffffff81181662 perf_event_mmap ([kernel.kallsyms]) ffffffff811cf5ed mmap_region ([kernel.kallsyms]) ffffffff811cfe6b do_mmap ([kernel.kallsyms]) ffffffff811b0dca vm_mmap_pgoff ([kernel.kallsyms]) ffffffff811cdb0c sys_mmap_pgoff ([kernel.kallsyms]) ffffffff81033acb sys_mmap ([kernel.kallsyms]) ffffffff81631d37 entry_SYSCALL_64_fastpath ([kernel.kallsyms]) heaptrack_gui 2228 135073.388677: 611329 cycles: ~~~~~ With this patch applied, the libdw unwinder will produce the same output as the libunwind unwinder. Signed-off-by: Nikson Kanti Paul Signed-off-by: Milian Wolff Cc: Jiri Olsa Cc: Namhyung Kim Link: http://lkml.kernel.org/r/20170601210021.20046-1-milian.wolff@kdab.com Signed-off-by: Arnaldo Carvalho de Melo Cc: Amit Shah Cc: David Woodhouse Cc: Greg Kroah-Hartman Cc: # 4.9 Signed-off-by: Sasha Levin --- tools/perf/util/unwind-libdw.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c index 046a4850e3df..ff32ca1d81ff 100644 --- a/tools/perf/util/unwind-libdw.c +++ b/tools/perf/util/unwind-libdw.c @@ -231,7 +231,7 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg, err = dwfl_getthread_frames(ui->dwfl, thread->tid, frame_callback, ui); - if (err && !ui->max_stack) + if (err && ui->max_stack != max_stack) err = 0; /* -- 2.19.1