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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BE9AEC6FD1C for ; Tue, 14 Mar 2023 15:46:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230164AbjCNPqp (ORCPT ); Tue, 14 Mar 2023 11:46:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231437AbjCNPqe (ORCPT ); Tue, 14 Mar 2023 11:46:34 -0400 Received: from smtp-fw-9103.amazon.com (smtp-fw-9103.amazon.com [207.171.188.200]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D169569065 for ; Tue, 14 Mar 2023 08:46:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1678808765; x=1710344765; h=references:from:to:cc:date:in-reply-to:message-id: mime-version:subject; bh=b8m7nO0Bmp5ymxlCAIQHK+OML+5cZteC5meaEPmcKCM=; b=kIqPMTdHgFVDKgVsAdVcVe/gH082b3rErxqTBm8XOqk6H/xAZPzyAMVH G5nBkJmyziHdS+0N4t23zP62cX9TIEemlykBRj23aOwVZMHU7LgJx+NYP Mu0RKdIeHjgSBTl0cuc87K+J5f9h28jmKRhYJA7JgAv7XtmnYPeo4o7HW k=; X-IronPort-AV: E=Sophos;i="5.98,260,1673913600"; d="scan'208";a="1112552210" Subject: Re: [PATCH v4 net-next 1/5] ethtool: Add support for configuring tx_push_buf_len Received: from pdx4-co-svc-p1-lb2-vlan3.amazon.com (HELO email-inbound-relay-pdx-2b-m6i4x-ed19f671.us-west-2.amazon.com) ([10.25.36.214]) by smtp-border-fw-9103.sea19.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Mar 2023 15:45:40 +0000 Received: from EX19D014EUA001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan3.pdx.amazon.com [10.236.137.198]) by email-inbound-relay-pdx-2b-m6i4x-ed19f671.us-west-2.amazon.com (Postfix) with ESMTPS id 31F79819CD; Tue, 14 Mar 2023 15:45:40 +0000 (UTC) Received: from EX19D028EUB003.ant.amazon.com (10.252.61.31) by EX19D014EUA001.ant.amazon.com (10.252.50.20) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.24; Tue, 14 Mar 2023 15:45:39 +0000 Received: from u570694869fb251.ant.amazon.com.amazon.com (10.85.143.174) by EX19D028EUB003.ant.amazon.com (10.252.61.31) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.24; Tue, 14 Mar 2023 15:45:30 +0000 References: <20230309131319.2531008-1-shayagr@amazon.com> <20230309131319.2531008-2-shayagr@amazon.com> <316ee596-e184-8613-d136-cd2cb13a589f@nvidia.com> <20230309225326.2976d514@kernel.org> <20230313120942.75599b8e@kernel.org> User-agent: mu4e 1.8.13; emacs 28.0.91 From: Shay Agroskin To: Jakub Kicinski CC: Gal Pressman , David Miller , , "Woodhouse, David" , "Machulsky, Zorik" , "Matushevsky, Alexander" , Saeed Bshara , "Wilson, Matt" , "Liguori, Anthony" , "Bshara, Nafea" , "Belgazal, Netanel" , "Saidi, Ali" , "Herrenschmidt, Benjamin" , "Kiyanovski, Arthur" , "Dagan, Noam" , "Arinzon, David" , "Itzko, Shahar" , "Abboud, Osama" Date: Tue, 14 Mar 2023 17:38:23 +0200 In-Reply-To: <20230313120942.75599b8e@kernel.org> Message-ID: MIME-Version: 1.0 Content-Type: text/plain; format=flowed X-Originating-IP: [10.85.143.174] X-ClientProxiedBy: EX19D039UWA004.ant.amazon.com (10.13.139.68) To EX19D028EUB003.ant.amazon.com (10.252.61.31) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Jakub Kicinski writes: > CAUTION: This email originated from outside of the > organization. Do not click links or open attachments unless you > can confirm the sender and know the content is safe. > > > > On Sun, 12 Mar 2023 14:41:39 +0200 Gal Pressman wrote: >> On 10/03/2023 8:53, Jakub Kicinski wrote: >> > On Thu, 9 Mar 2023 19:15:43 +0200 Gal Pressman wrote: >> >> I know Jakub prefers the new parameter, but the description >> >> of this >> >> still sounds extremely similar to TX copybreak to me.. >> >> TX copybreak was traditionally used to copy packets to >> >> preallocated DMA >> >> buffers, but this could be implemented as copying the packet >> >> to the >> >> (preallocated) WQE's inline part. That usually means DMA >> >> memory, but >> >> could also be device memory in this ENA LLQ case. >> >> >> >> Are we drawing a line that TX copybreak is the threshold for >> >> DMA memory >> >> and tx_push_buf_len is the threshold for device memory? >> > >> > Pretty much, yes. Not an amazing distinction but since TX >> > copybreak can >> > already mean two different things (inline or DMA buf) I'd err >> > on >> > the side of not overloading it with another one. >> >> Can we document that please? > > Shay, could you add a paragraph in the docs regarding copybreak > in v5? Document that tx_copybreak defines the threshold below which the packet is copied into a preallocated DMA'ed buffer and that tx_push_buf defines the same but for device memory? Are we sure we want to make this distinction ? While the meaning of both params can overlap in their current definition, the motivation to use them is pretty different. A driver can implement both for different purposes (and still copy both into the device). I'll modify the documentation in next version