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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0B007C47094 for ; Mon, 14 Jun 2021 19:51:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EA94E611C0 for ; Mon, 14 Jun 2021 19:51:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234593AbhFNTxV (ORCPT ); Mon, 14 Jun 2021 15:53:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42506 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234214AbhFNTxQ (ORCPT ); Mon, 14 Jun 2021 15:53:16 -0400 Received: from mail.monkeyblade.net (shards.monkeyblade.net [IPv6:2620:137:e000::1:9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7C800C061574; Mon, 14 Jun 2021 12:51:13 -0700 (PDT) Received: from localhost (unknown [IPv6:2601:601:9f00:477::3d5]) by mail.monkeyblade.net (Postfix) with ESMTPSA id 251124D079864; Mon, 14 Jun 2021 12:51:12 -0700 (PDT) Date: Mon, 14 Jun 2021 12:51:11 -0700 (PDT) Message-Id: <20210614.125111.1519954686951337716.davem@davemloft.net> To: mcroce@linux.microsoft.com Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, peppe.cavallaro@st.com, alexandre.torgue@foss.st.com, kuba@kernel.org, palmer@dabbelt.com, paul.walmsley@sifive.com, drew@beagleboard.org, kernel@esmil.dk Subject: Re: [PATCH net-next] stmmac: align RX buffers From: David Miller In-Reply-To: <20210614022504.24458-1-mcroce@linux.microsoft.com> References: <20210614022504.24458-1-mcroce@linux.microsoft.com> X-Mailer: Mew version 6.8 on Emacs 27.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.6.2 (mail.monkeyblade.net [0.0.0.0]); Mon, 14 Jun 2021 12:51:12 -0700 (PDT) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org But thois means the ethernet header will be misaliugned and this will kill performance on some cpus as misaligned accessed are resolved wioth a trap handler. Even on cpus that don't trap, the access will be slower. Thanks.