From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9D1E14E36EC; Thu, 17 Sep 2026 19:42:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789674174; cv=none; b=Z7XxIhtkGjIkF3AhYJTPjtbEV5osZVVMWilee2bfNw/SU59OfogF0glBrYtBCl4CvbzplQYwODrwg+XFLYihXKONMhdN1cXiwXYiQOsyXavD4CwnBH5txBtHor5cwk+mlgtHws0uYkaqBFx7ZMALpjtPw8qVdOq+0ilOTE8PV5o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789674174; c=relaxed/simple; bh=k2rS+F0P3MHx+9e0fz/nBmTWD9HXaB4FKGnbXf/FFgQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=T2/XsVxKp4I7MB77+M/3aazFfmYprxuSC44nrPZur1UJj/HceE2qCTbg2+vU1CHdgfMnq8v6GKQShYSEIrDNUxPCvWSe5q0yWNKs9SRsJurSNvEtK+ExxmRkZXi/xjKgv2d7xq9QEygnbcv8NYqx6M30nqXvnPcCs5Jj+k9R3/U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QEAswLsJ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QEAswLsJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E94031F000FF; Thu, 17 Sep 2026 19:42:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789674172; bh=PkRN80BoSYgUIdgeE3XHmHynLUQObuBpZsM5VGJ/hZ8=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=QEAswLsJV5CT5idl2b0sxECKt4RBnyFOYUhJeV8VSDp7LPI5q2uG0MitNu8vlrrGj GgP3f04l+0g2WO7Dw5awGdDXIeJH1+hlD5eteCdUqsYsZsKEHJot2zsQGiqsRqy8QV SXyJCnsalvj1JC+2CD4Ia7CbcDMentUQTCRQPyjilTKQXjJF/n1wcyHIpueWwqegca iexi0eQKo1IVM6WiNYXwgSA66Y8LNUF1DQzWeuBGNKtPcG+iwHiFB2sW9lhh+LTGNT i3DhH67X4z6x+NB5d58jYolAijG3u4bGwKbJBQaaayCSIrgwL4431CwUsDA/CZgmNo sabJIf79IKUwQ== Date: Thu, 17 Sep 2026 20:42:36 +0100 From: "Lorenzo Stoakes (ARM)" To: Linus Torvalds Cc: Nathan Chancellor , Nicolas Schier , Nick Desaulniers , Bill Wendling , Justin Stitt , Masahiro Yamada , Alexey Gladkov , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Arnd Bergmann , Catalin Marinas , Will Deacon , Mark Rutland , Ard Biesheuvel , Ilias Apalodimas , Josh Poimboeuf , Peter Zijlstra , Miguel Ojeda , Boqun Feng , Gary Guo , =?utf-8?B?QmrDtnJu?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Daniel Almeida , Tamir Duberstein , Alexandre Courbot , Onur =?utf-8?B?w5Z6a2Fu?= , Jonathan Corbet , Randy Dunlap , Kees Cook , "Gustavo A. R. Silva" , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-efi@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-doc@vger.kernel.org, Jens Axboe , linux-hardening@vger.kernel.org Subject: Re: [PATCH v3 00/20] kbuild: significantly speed up kernel builds Message-ID: References: <20260917-build-speedup-v3-0-9ecf4163ff36@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Sep 17, 2026 at 06:36:18PM +0100, Lorenzo Stoakes (ARM) wrote: > On Thu, Sep 17, 2026 at 10:15:26AM -0700, Linus Torvalds wrote: > > On Thu, 17 Sept 2026 at 09:06, Lorenzo Stoakes (ARM) wrote: > > > > > > == defconfig FULL build == > > > > > > before after delta > > > ---------------------------------- > > > Threadripper, gcc 32.5s 26.3s -6.1s (-19%) > > > Threadripper, clang 34.5s 27.2s -7.3s (-21%) > > > EPYC, gcc 28.7s 20.6s -8.1s (-28%) > > > EPYC, clang 39.8s 32.2s -7.6s (-19%) > > > M2, gcc 519.3s 512.4s -6.9s (-1%) > > > M2, clang 634.5s 569.4s -65.1s (-10%) > > > > There's something odd going on with that M2 gcc build. Why is it such > > an odd duck? > > Ugh dear lord I think the LLM somehow corrupted the numbers... Let me > re-run those myself locally and come back with the actual times! OK numbers are in: M2, gcc 564.7s 512.1s -52.6s (-9%) M2, clang 615.1s 564.1s -51.0s (-8%) >From the v1: M2, gcc 564.0s 512.4s -51.6s (-9%) M2, clang 616.1s 569.4s -46.7s (-8%) (Tested as per the cover letter pre-reqs, i.e. applying dependent series first etc.) Not sure on the -5s delta on the clang build :) that might have been me being more disciplined this time to not use the laptop at the same time. But broadly in line with the original numbers. > > > > > Linus > > -- > Cheers, Lorenzo -- Cheers, Lorenzo