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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 EE6D5C43458 for ; Mon, 29 Jun 2026 12:22:02 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4gpllF3yKRz2ySS; Mon, 29 Jun 2026 22:22:01 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip=213.95.11.211 ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1782735721; cv=none; b=BWIjiLl1NZAn+A2lXNUi0iEqUORPMZNmMx/0lbDcqoTIiiWq5ZGtQzsopxFNZiNpEO6gHqPUYZlDeJ5U+yK9RkbGEpgmk3zKcRBcP/gEXAXwvgdUpqsX+udCl/rlO3Wslmf0qBt3j72knYHMEs88AfRuJ8rbrx9Tp6kWUDK13bJYRcdCo3S6D5ZhOA+xWOadOdjYf7vNshFM8GjXTRrflvTiBPRVlepcrFmVA0LAQzKpwvkoh09GHjyXx2FHMAe+Fh23hL5ZwYVOxdQL7EBl4nACu7vDbOaNbh/+gYlYQqoLGidEbvThuCXfFxsIIZis48eOzrg6ap7JBQLGEqBANQ== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1782735721; c=relaxed/relaxed; bh=dircqAEtLKhzXLNYPYvdhjyZBvBeGfOpZZwNNS747TM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WVuF2fdKOyhvuJ1DqRM1Xy//ifF0girS6Pm/+XsD2RVv5FlS1uzoTWKsD3JhZSBHvOZqK1uoTcVvvC32vUToUuPJu+RjqGmXDsNMdzsto+Sq1nmZGWmicAARs6lWLMwwU6A41RfX6asSktSN6dohKqhhXAnQyS6EVyCfA8Eo0ICkGSuEtQE0yP3EqVoxvOlVc1DiBbneQ573uJCP7eM+x7qmUxIjkH/fJXPOjO6xx1TBLXU75kPd5oVbncq1RztaHVLY1zurSw3yw+NbmdltUjFrU5XHS0Hh9NrVZ1iOtJC709/WuV+VcdJf3+c1pmOSIwJzcYHrcOa3NzkfpcdqQQ== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=lst.de; spf=pass (client-ip=213.95.11.211; helo=verein.lst.de; envelope-from=hch@lst.de; receiver=lists.ozlabs.org) smtp.mailfrom=lst.de Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=lst.de Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lst.de (client-ip=213.95.11.211; helo=verein.lst.de; envelope-from=hch@lst.de; receiver=lists.ozlabs.org) Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4gpllD6Vkmz2xYh for ; Mon, 29 Jun 2026 22:22:00 +1000 (AEST) Received: by verein.lst.de (Postfix, from userid 2407) id E5ACE68AFE; Mon, 29 Jun 2026 14:21:52 +0200 (CEST) Date: Mon, 29 Jun 2026 14:21:52 +0200 From: Christoph Hellwig To: "H. Peter Anvin" Cc: Christoph Hellwig , Andrew Morton , Catalin Marinas , Will Deacon , Ard Biesheuvel , Huacai Chen , WANG Xuerui , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Herbert Xu , Dan Williams , Chris Mason , David Sterba , Arnd Bergmann , Song Liu , Yu Kuai , Li Nan , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-crypto@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-arch@vger.kernel.org, linux-raid@vger.kernel.org Subject: Re: cleanup the RAID6 P/Q library v3 Message-ID: <20260629122152.GA21344@lst.de> References: <20260518051804.462141-1-hch@lst.de> <20260518141205.c100f76eec5f58e78bbbf7af@linux-foundation.org> <20260519082432.GA14956@lst.de> <7d8efc7c-65e3-49f8-9381-910de7affef2@zytor.com> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7d8efc7c-65e3-49f8-9381-910de7affef2@zytor.com> User-Agent: Mutt/1.5.17 (2007-11-01) On Fri, Jun 26, 2026 at 05:52:18PM -0700, H. Peter Anvin wrote: > On 2026-05-19 01:24, Christoph Hellwig wrote: > > > > raid6: rework registration of optimized algorithms > > > > - avx2 instead of avx512 is probably the right thing for no > > benchmarking, but if it was intentional (it wasn't), that should > > be document. So I'll just switch back to the previous version to > > keep the state of the art > > It is unlikely to be the right thing *going forward*, though. > > The very unfortunate performance inversion is likely model-specific. It is one > of those things where you largely would have to have a list of quirks :( Note that the default is still to benchmark the implementations. This is just about the case where the user explicitly disabled that benchmark-based selection.