Received: by 2002:a05:6a10:206:0:0:0:0 with SMTP id 6csp3038033pxj; Mon, 14 Jun 2021 12:54:27 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwNuQJfX+XMFBlKu67VN4K5PQAGg6L8KtvLXkiN/qEDeH4wYgDtLuItSkFErdN3XhJ1KzAN X-Received: by 2002:a05:6402:2689:: with SMTP id w9mr18333546edd.375.1623700466912; Mon, 14 Jun 2021 12:54:26 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1623700466; cv=none; d=google.com; s=arc-20160816; b=TXoQxReehbjFVnqaPIq5ZGFHAjlQlggUHiAfyh4IrQL+utFzrcipsmplDLnWYVuuwI Rzkga91D7ZdxlrWxjD9VQe/AaQp0qn4wv8pWERA2sJM3WmOCihzqsK/TjC9hP8+XJywz hCdU2+nUsEqs1plH2Ef7AmlHQ1QZu/c+m6Tn+ipBjFX+sZAOKPc8YVnbmjBCQTrUZtMB ItJyonxZpZ1ecNHqpJgI1sm4gX4HdF9Q9+TMEE/h+SFnKH8ICSK4pxyRFdFZkJJxV0pd tyDSpQ482UOuP9bfXSuvb/Tf2i/rlyveXqTP3pJt33vgCrrAEEZRLsl0wSd8Lmz3H8Aa preQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:from:subject:cc:to:message-id:date; bh=+xxp42C0V+htGCyLA/pibIULpRwDSVe670vYDcXip3Q=; b=NXm4xP49VciK6zQmlCOCSsTDB1QMZwOpH13h590kWnSXOZKrDhKD/L9R9d//VSWctj VbDkMn/keGtzTCowy4DD3EjIlqdvTW22yBiPDlELnYLnr4d3qLJQqnkOAPlegiZyuY90 ATMK/UoCChKK/w83JPtPJsbkHw/ItHYju6v0B5ywI52G4aC9YGmI9dJyrM8z1B8vXHAG TY5MQrnr3LtamJ0i4Gy07mlKDsGuhUvnApvbQoUSJezcVm+QXSj4iE7y4bt+wnxwRHMZ Ghfgb/yw1VP2Zh6q3OcjagArcOzSR2BEuW3X9C4ySpATECDWZcncgbQ51AHj2R6OneCX TL3A== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id v21si13026941edi.397.2021.06.14.12.54.03; Mon, 14 Jun 2021 12:54:26 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234248AbhFNTxS (ORCPT + 99 others); Mon, 14 Jun 2021 15:53:18 -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.