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 388044078E1; Mon, 14 Sep 2026 15:41:40 +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=1789400501; cv=none; b=uU/wvXmFg3t4UKsv8GbitJK8cKF0x8Tfu02z+lU/jrRdBWBSC5jxI1D7xHX8W5PF3lHmKNXMOwDeAqeLGiUMnLO5goySR1qinQGxvkLGGMmAQiDbnPi6s1svbWTxQKx2bs2l+pQH2tCOj+Zy6Pq4l2TSfJC2LhHMAqt4EA/rRZs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789400501; c=relaxed/simple; bh=1C11XBaWmlMwkcWzSZFuI1CdhCAjTwmTkCRbColifqU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Q5XWwjTfDIRMNXpDSOJqc2WVJIkiuB7EsHdD15jKJMH21B3z5Rewhw95TZKvQq5mEk3HJPUfBeruMKmbSP2Ygm0+Ngz7KX2hZDCnEFhGarcld8jtda93gTMu2mjP2fxlPF8c1M5AxpakOG2u0PADbC1fvVlrER4u7cY4pw9SauU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dfP1LAhO; 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="dfP1LAhO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D65451F000FF; Mon, 14 Sep 2026 15:41:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789400499; bh=LlgemL/nYzkX38RnFaAaX6AJ/gCOHK0upUXgQVTNyVk=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=dfP1LAhOfyUCT1PylVrcF075Tfg6+7c5SvnpIHQ+rAbO8bxKF55c7/ZDbzYdndWLQ PFE8QcEVlU853PPHlOHXNB8/pzzHUCWymO2aS6uFlt3IYh0wjA8iV0mvk+LIKqNU57 Cl02xJUIbJkMswfgRghpxodJWaa5683/jeF5m+wZTyUytnrSFFqKGZfkF5P947C32p 7kUNwMkritvIBif2Omva1r+N8dm7wc+8s5PpwgnhdwIp7PRrU5+FtZo4z0rBDxxV1q 82HVjM3lab6/f7lJ1DGldaHS+d6L94gZiJAKM/Bczd23Em6D9FZB1fBvwiZPrVoB6t jZqdnBbutFClg== Date: Mon, 14 Sep 2026 08:41:39 -0700 From: Kees Cook To: "Lorenzo Stoakes (ARM)" Cc: Linus Torvalds , 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 , =?iso-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Daniel Almeida , Tamir Duberstein , Alexandre Courbot , Onur =?iso-8859-1?Q?=D6zkan?= , Jonathan Corbet , Randy Dunlap , "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 v2 00/21] kbuild: significantly speed up kernel builds Message-ID: <202609140833.88C0E16E50@keescook> References: <20260914-build-speedup-v2-0-39817ec5db23@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: <20260914-build-speedup-v2-0-39817ec5db23@kernel.org> On Mon, Sep 14, 2026 at 10:21:59AM +0100, Lorenzo Stoakes (ARM) wrote: > This series makes allmodconfig builds up to 36% faster, ... This is very nice! > incremental builds > up to ~70% faster, and noop builds up to ~90% faster. Some of the changes for this seem to add complexity that I'm not sure is balanced against the gain? I am still looking through the series, though, maybe I'll change my opinion. ;) > == allmodconfig FULL build == Did you try Clang CONFIG_LTO=y builds? > == LLM usage == > [...] > I extensively audited and rewrote a lot of it, and heavily edited commit > messages, the cover letter and comments. I feel like the commit logs still need a lot of work. The LLM verbosity problem appears in many of them, for example spending 80% of the commit log describing every step of some process as background before getting to the actual change. I think a human writing this would be much more terse about the background. I have, however, been known to be too terse in my own commit logs. :P > [...] > Nothing too controversial was included. There are further improvements that > could be made, but they would either by very invasive (large scale C header > changes) or generate diminishing returns. One area I think might solved via an LLM is the 3-pass kallsyms stuff. If we could get a deterministic kallsyms build in 1 pass, that would be very nice. A lot of people have tried, but it has eluded upstreaming. -Kees -- Kees Cook