From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr1-x430.google.com (mail-wr1-x430.google.com [IPv6:2a00:1450:4864:20::430]) by sourceware.org (Postfix) with ESMTPS id 027C33858D20 for ; Fri, 27 Jan 2023 06:30:28 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 027C33858D20 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=adacore.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=adacore.com Received: by mail-wr1-x430.google.com with SMTP id d14so4010666wrr.9 for ; Thu, 26 Jan 2023 22:30:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=adacore.com; s=google; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=QeTTDofOy1+ZayKodRqnwwUjx+9BugrvlGf01suwbqM=; b=jas+vDP+gVlNoiqr6/nnLyyOg33O0x5AV8QsY98OJtgWAZbnRJ7QfTdxEgZh23od6q GX/12be5tcJ9gHPj1jzy/h998DSSpLP+era+q9VmE8L0FjA0qE4hpFbx509Yq2C9WO3z EXEgKq5+TlkC1l7w2mWK0GgWxfJKFPDVXCHYprLz+YQtEUGjq39F+4OkQiGdA0kplstP zVNzbrlhoyEdVPaG4Ek+AdAgkoMv2qFsQW+01EnJsq2voQJyQSjt4haW9ZUjUV0lISUI qsiJYeQLYg3aRSpzkmR1tdIQzTr/dv8A2/xy2NuOXIRWVH6g4D2m4kQqdkcDdd6/wFSv yf1w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=QeTTDofOy1+ZayKodRqnwwUjx+9BugrvlGf01suwbqM=; b=1yCCNRh+6RZmj5kBMRFO1ZeZhMzWUiGk6Q2TcFOOwFD3TTEjvxxsc4zfMopqrxGem2 EOphUUo58Z3Troa0lM2O94nyQ36XPbMHdwMtBTb0IW4HI+BIrYtn3CQW38/I1J7FQuiK XswRUfhy50qSKI9mlJi2veikuWCsnMTQXRlmCZhArCmfQ1yrBqeTRjZ0VEJCU47eNvdt i+MzHCSMMP+OVBKw/2+ArGoZvKK8UodOyj7ME5oVZBfh2WrHZdfYmanQbQomWSz6N//l JRX7L/ew3bw4K0g1v48EE2GvqFzaU+li6NPcRgUV4rXpJ4+ynVNfUto7etKPBLPObZgU dlFA== X-Gm-Message-State: AFqh2kqNtMLEI0Ngrc69u/L/39l9K2KKHNWZLy6PamiCGD4zuLPDeDaW onsJ3H6SiP4+K+0ZMNcnuu8MkbU6p93Zopg= X-Google-Smtp-Source: AMrXdXutZpMnQks209/WvZJZ1sbJhTSLvSi9YpNk2z5RhP+ktDVewo9MuVhGWIJxqax0q1Rrcg//Fw== X-Received: by 2002:adf:f605:0:b0:2bd:be31:cd77 with SMTP id t5-20020adff605000000b002bdbe31cd77mr30709322wrp.30.1674801026803; Thu, 26 Jan 2023 22:30:26 -0800 (PST) Received: from takamaka.gnat.com ([2a01:cb22:1d5:1100:1566:5a8c:ca35:e491]) by smtp.gmail.com with ESMTPSA id k4-20020a5d66c4000000b002bdc19f8e8asm3154333wrw.79.2023.01.26.22.30.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Jan 2023 22:30:26 -0800 (PST) Received: by takamaka.gnat.com (Postfix, from userid 1000) id 3AB5E82761; Fri, 27 Jan 2023 10:30:24 +0400 (+04) Date: Fri, 27 Jan 2023 10:30:24 +0400 From: Joel Brobecker To: Torbjorn SVENSSON , simon.marchi@polymtl.ca, tom@tromey.com Cc: Joel Brobecker , gdb-patches@sourceware.org, luis.machado@arm.com Subject: Re: GDB 13 release -- 2023-01-21 Update Message-ID: References: <95dc547e-59f8-95b3-903c-138d8842cea0@foss.st.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <95dc547e-59f8-95b3-903c-138d8842cea0@foss.st.com> X-Spam-Status: No, score=-3.9 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Hello, > > * [Torbjorn] tdep/29738 > > Arm M-profile dwarf2 unwinder performance suffers from exponential growth > > https://sourceware.org/bugzilla/show_bug.cgi?id=29738 > > > > patch v3, 2023-01-19, reviewed 2023-01-20: > > https://sourceware.org/pipermail/gdb-patches/2023-January/195915.html > > I just pushed this for master. > Is it okay to also push the 2 patches to gdb-13-branch? For the avoidance of doubt, my understanding is that we are talking about the following two patches: commit d72ba177c85f2ad18d0dcabdd8844532c9acb819 Author: Torbjörn SVENSSON Date: Thu Nov 17 12:17:53 2022 +0100 Subject: gdb: dwarf2 generic implementation for caching function data ... and ... commit 5cf11483141a58314834653003e49709b47822d5 Author: Torbjörn SVENSSON Date: Thu Nov 17 12:18:20 2022 +0100 Subject: gdb/arm: Use new dwarf2 function cache I hope I having missed any other patch! The first one adds, as the subject indicates, a framework for caching frame-related information, and the second patch takes advantage of that framework, Luis marked the corresponding PR as "important to fix", so I'm assuming the impact if we do not backport is significant (exponentional performance degradation). I was confused into thinking that this would "only" impact Cortex-m without security extensions, but maybe it's the opposite actually. So the next question is, what is the potential impact if we backport the patch and there is a bug in it: - Well, it touches the generic Arm unwinding code, so worse case scenario, DWARF-based unwinding is broken? - With that said, the patch appears to simply add a cache, so the logic of it all doesn't appear to be extremely complicated. So I would rate the risk to be low. If Tom and/or Simon agree, my assessment is that it is fine to backport those two patches onto the gdb-13 branch. -- Joel