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 7796BCD4F26 for ; Fri, 26 Jun 2026 05:47:54 +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=bMseHbvJydZFqU3q4odAWqNXjvvpbA9RMs+RKNizO6M=; b=r52GhoJVr3iiwB1Gtv2tn5sa48 X23UV7swHKI30inNCA3M8pBisvMcj5esVALueUMVzyYp/0oKao2KDai+hdewx92nR2KmGkbJr9h9t S7xQ0cMxD0E1FLXP4Dj8jN6uCLLMbrohNTKuGepL5iKAQsD2DBQW4MJZW+ycexgV18yNXc5F5Swi9 jwoW0B2CE7gRp+SIK3pwK5O9844MyVkP/ZT55jqhQVmi+jKhpQ2kq9MiJOJQM3DnJ5t3F52G8ZWHh pNRnNMiT1EFzx9owmicdXb68+qhn6uWiQd9SdTdJIz6nW+aJw9zJdsq+7igNLbaSzEjdcoyQxUAJ+ vGBjE1lg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wczPu-0000000AXgN-0zl6; Fri, 26 Jun 2026 05:47:54 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wczPr-0000000AXfY-3cm6 for linux-um@lists.infradead.org; Fri, 26 Jun 2026 05:47:53 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 4496268B05; Fri, 26 Jun 2026 07:47:49 +0200 (CEST) Date: Fri, 26 Jun 2026 07:47:49 +0200 From: Christoph Hellwig To: Eric Biggers Cc: x86@kernel.org, linux-um@lists.infradead.org, linux-raid@vger.kernel.org, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, Andrew Morton , David Laight Subject: Re: [PATCH 8/8] lib/raid/xor: x86: Add AVX-512 optimized xor_gen() Message-ID: <20260626054749.GD9629@lst.de> References: <20260626043731.319287-1-ebiggers@kernel.org> <20260626043731.319287-9-ebiggers@kernel.org> <20260626054731.GC9629@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260626054731.GC9629@lst.de> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260625_224752_050420_098B5791 X-CRM114-Status: GOOD ( 15.11 ) 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 Fri, Jun 26, 2026 at 07:47:31AM +0200, Christoph Hellwig wrote: > On Thu, Jun 25, 2026 at 09:37:31PM -0700, Eric Biggers wrote: > > + if (IS_ENABLED(CONFIG_X86_64) && boot_cpu_has(X86_FEATURE_AVX512F) && > > + !boot_cpu_has(X86_FEATURE_PREFER_YMM)) { > > + /* AVX-512 will be the best; no need to try others. */ > > + /* !PREFER_YMM excludes CPUs with overly-eager downclocking. */ > > Can you turn this into a single block comment using full sentences? > Right now the two separate comments almost feel contradictory even > if I get what you mean. While you're at it also through in a blurb > why we dont bother with AVX-512 (number of register, no one in the right > mind would bother running high performance code on modern cpus in 32-bit > mode). Otherwise looks good, btw: Reviewed-by: Christoph Hellwig