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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9508FF30262 for ; Sun, 15 Mar 2026 14:16:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=skGShgRopWYLAHQVMA1zpv2Nb5W8Z646MfW2V64tqwk=; b=wiyCz5n3spehED4ujRq2lFDH6k rAvU+u5g3GvpRFun3ORw87SWZWZVPz4c204TPKq8FX7XrMWCpqHvIIcBkvvN5m75pVwgxd5n/aDYW m1a3guenTQFdDRR3pUqGCAVm0juBJ79vHBgdDliUt6EQEt6YTzuKg3O1b3/zQBxwGaZ0yVuUU/6Iq Pl7m7NPzo+b/U4SzYDbH0Jeb/oZJXoZFL7iEHAb2Kh98/lzpV/pSDT33mN/6oqA89W82ww32WHs9C wd6jMEEOsKvmQm6Xl3XE/QAjoDoSvCLJNpeMgwwpnnLx4guI5mvJPeK31DI/6Qqs12Zj+1yjST9Nx SJr0QAAg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w1mGJ-00000002ehW-2CYv; Sun, 15 Mar 2026 14:16:11 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1w1mGG-00000002eh5-3vnd for linux-um@lists.infradead.org; Sun, 15 Mar 2026 14:16:10 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id E0D074411F; Sun, 15 Mar 2026 14:15:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7DF01C4CEF7; Sun, 15 Mar 2026 14:15:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773584159; bh=agFxp7/+DmzOfwyTxuEGMhbMU3mctxR6EiAxomWVZjA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=roL1M/sncI7syFKC+9EAQl1eCZCHmJRgd6pDWPCUMZ1EXZw6eMIBYdBqGlooV8+Cz WG3hLBXqLVlZAyHyTeksN6hrbhZxwYTrK7Wd4q8RIbgN1JcM0aQkL0CIRTAxbnky/N llZEm7aaanH9Q+Arg3PCOb5TdJxe8lOcuZ9t2ijKVqCKiy04H4pgFLSfDUtojc9k84 4MyFWx4I3cT5s7XGmir14ybXW295nx5o76Zy7Dtz1gMlHGjQhEZSFXCwkwP5OrFRgK kkqBIrGUBwc5g+NXoR9z7J1yP9qE+pYk0UY42I+bT0OuTv4iqeWqi3wwSlE1yzF+3m 2I9oF3TCISnKw== Date: Sun, 15 Mar 2026 10:15:58 -0400 From: Sasha Levin To: Peter Zijlstra Cc: Chuck Wolber , nathan@kernel.org, Matt.Kelly2@boeing.com, akpm@linux-foundation.org, andrew.j.oppelt@boeing.com, anton.ivanov@cambridgegreys.com, ardb@kernel.org, arnd@arndb.de, bhelgaas@google.com, bp@alien8.de, chuck.wolber@boeing.com, dave.hansen@linux.intel.com, dvyukov@google.com, hpa@zytor.com, jinghao7@illinois.edu, johannes@sipsolutions.net, jpoimboe@kernel.org, justinstitt@google.com, kees@kernel.org, kent.overstreet@linux.dev, linux-arch@vger.kernel.org, linux-efi@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-um@lists.infradead.org, llvm@lists.linux.dev, luto@kernel.org, marinov@illinois.edu, masahiroy@kernel.org, maskray@google.com, mathieu.desnoyers@efficios.com, matthew.l.weber3@boeing.com, mhiramat@kernel.org, mingo@redhat.com, morbo@google.com, ndesaulniers@google.com, oberpar@linux.ibm.com, paulmck@kernel.org, richard@nod.at, rostedt@goodmis.org, samitolvanen@google.com, samuel.sarkisian@boeing.com, steven.h.vanderleest@boeing.com, tglx@linutronix.de, tingxur@illinois.edu, tyxu@illinois.edu, wentaoz5@illinois.edu, x86@kernel.org Subject: Re: [RFC PATCH 0/4] Enable Clang's Source-based Code Coverage and MC/DC for x86-64 Message-ID: References: <20250829181007.GA468030@ax162> <20251014232639.673260-1-sashal@kernel.org> <20251015073701.GZ3419281@noisy.programming.kicks-ass.net> <20251015092145.GB3419281@noisy.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20251015092145.GB3419281@noisy.programming.kicks-ass.net> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260315_071609_023911_261AD23E X-CRM114-Status: UNSURE ( 9.37 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org On Wed, Oct 15, 2025 at 11:21:45AM +0200, Peter Zijlstra wrote: >On Wed, Oct 15, 2025 at 08:26:50AM +0000, Chuck Wolber wrote: >> Optimization makes it nearly impossible to correlate GCov results back to >> actual lines of source. llvm-cov instruments at the AST level which enables >> precise mapping back to source code regardless of optimization level. >> >> >> A detailed rundown on this issue can be found here[1], with the most relevant >> excerpt reproduced here: > >Yes read and understand this, but that doesn't mean you have to have 3 >different kernel interfaces for all of this, right? To clarify, are you suggesting that we'll have something like a single /sys/kernel/debug/coverage interface that is producing the same structured output whether we use gcov or llvm? -- Thanks, Sasha