From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 32F0343D11; Thu, 21 Mar 2024 09:29:07 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id CC43D42830; Thu, 21 Mar 2024 09:29:06 +0100 (CET) Received: from wfhigh4-smtp.messagingengine.com (wfhigh4-smtp.messagingengine.com [64.147.123.155]) by mails.dpdk.org (Postfix) with ESMTP id D96E94028B for ; Thu, 21 Mar 2024 09:29:04 +0100 (CET) Received: from compute6.internal (compute6.nyi.internal [10.202.2.47]) by mailfhigh.west.internal (Postfix) with ESMTP id 62C6A18000B4; Thu, 21 Mar 2024 04:29:00 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute6.internal (MEProxy); Thu, 21 Mar 2024 04:29:01 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=monjalon.net; h= cc:cc:content-transfer-encoding:content-type:content-type:date :date:from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:subject:subject:to:to; s=fm2; t=1711009740; x=1711096140; bh=g5ZO8bDZH+qJAxsjpgyWktfHdr0WQmV/fXqpRfAAPGs=; b= usZpJCx46GTRFn4aW6K6NcaGbVGXBLIhw1uwi2ggDaCkItZ2y1BhnwHdgf4q0I3R NReIJbBeYerzA9Av/cStblHGhdm2Bul4CcGVN/C7AVzZKIiteniTl4RSzdwTcQbi pRb7nm7HY7hueOJYUiPh3EYNP03i4Nq/K6HLSVxPfzvz8vaNVO2EaE+IGpGQBNxN 8gugVnvxCwNYJNBnBSZvHIaNWVyBeFn34Rrve66BO30yUDSEh0qQKeb535zWbe3i yEwRdaRpGQxgLwLyf1uxVB3PYgQnNB/QaPcEFC+rN33V1BdG1mqIopDnuzaP7BmJ imyQqjvqrOHo4pMZZGGJTA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-transfer-encoding :content-type:content-type:date:date:feedback-id:feedback-id :from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:subject:subject:to:to:x-me-proxy:x-me-proxy :x-me-sender:x-me-sender:x-sasl-enc; s=fm2; t=1711009740; x= 1711096140; bh=g5ZO8bDZH+qJAxsjpgyWktfHdr0WQmV/fXqpRfAAPGs=; b=G GVh21PXZkQOCMngCl4x92ytPeiHmG6r+typ6FC4Xb5600MjXMqiDLSM2G/OUOQCZ LnpYW2hojoOlEmdcK7Rx+07CwUlDu+lvo07eXp/lFBO9rZfpD81qbOuS4WyXYeqM Izksf9ZQJT8A1os18wzx9vXVQvt/dxKx62FMr1JEPO/OjISGPikPxSUSJ3Fl4KbZ oIwCZwR3Sm1PJFigjq6tvJw0X2DonCfpJlmFyYnM2ONRu/G7oAc/r5l0ZyEhO/+h YBmPw7E0HCEAuHb+bDs+FqsqtBr2KsPnOOY4nTQI/9PGwR6zaz/y9+vQNuUut6ZN ySGcUDFN7ZLBxJvUZ/b6A== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvledrleehgdduudelucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhephffvvefufffkjghfggfgtgesthhqredttddtjeenucfhrhhomhepvfhhohhm rghsucfoohhnjhgrlhhonhcuoehthhhomhgrshesmhhonhhjrghlohhnrdhnvghtqeenuc ggtffrrghtthgvrhhnpeegtddtleejjeegffekkeektdejvedtheevtdekiedvueeuvdei uddvleevjeeujeenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfh hrohhmpehthhhomhgrshesmhhonhhjrghlohhnrdhnvght X-ME-Proxy: Feedback-ID: i47234305:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Thu, 21 Mar 2024 04:28:57 -0400 (EDT) From: Thomas Monjalon To: Damodharam Ammepalli , huangdengdui Cc: Ferruh Yigit , dev@dpdk.org, aman.deep.singh@intel.com, yuying.zhang@intel.com, andrew.rybchenko@oktetlabs.ru, liuyonglong@huawei.com, fengchengwen@huawei.com, haijie1@huawei.com, lihuisong@huawei.com Subject: Re: [PATCH 0/3] support setting lanes Date: Thu, 21 Mar 2024 09:28:54 +0100 Message-ID: <28052301.gRfpFWEtPU@thomas> In-Reply-To: <21ed4b3f-348b-4cf8-91d3-8d42874d7d35@huawei.com> References: <20240312075238.3319480-1-huangdengdui@huawei.com> <21ed4b3f-348b-4cf8-91d3-8d42874d7d35@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org 21/03/2024 03:02, huangdengdui: >=20 > On 2024/3/20 20:31, Ferruh Yigit wrote: > > On 3/18/2024 9:26 PM, Damodharam Ammepalli wrote: > >> On Mon, Mar 18, 2024 at 7:56=E2=80=AFAM Thomas Monjalon wrote: > >>> > >>> 12/03/2024 08:52, Dengdui Huang: > >>>> Some speeds can be achieved with different number of lanes. For exam= ple, > >>>> 100Gbps can be achieved using two lanes of 50Gbps or four lanes of 2= 5Gbps. > >>>> When use different lanes, the port cannot be up. > >>> > >>> I'm not sure what you are referring to. > >>> I suppose it is not PCI lanes. > >>> Please could you link to an explanation of how a port is split in lan= es? > >>> Which hardware does this? > >>> > >> This is a snapshot of 100Gb that the latest BCM576xx supports. > >> 100Gb (NRZ: 25G per lane, 4 lanes) link speed > >> 100Gb (PAM4-56: 50G per lane, 2 lanes) link speed > >> 100Gb (PAM4-112: 100G per lane, 1 lane) link speed > >> > >> Let the user feed in lanes=3D< integer value> and the NIC driver decid= es > >> the matching combination speed x lanes that works. In future if a new = speed > >> is implemented with more than 8 lanes, there wouldn't be a need > >> to touch this speed command. Using separate lane command would > >> be a better alternative to support already shipped products and only n= ew > >> drivers would consider this lanes configuration, if applicable. > >> > >=20 > > As far as I understand, lane is related to the physical layer of the > > NIC, there are multiple copies of transmitter, receiver, modulator HW > > block and each set called as a 'lane' and multiple lanes work together > > to achieve desired speed. (please correct me if this is wrong). > >=20 > > Why not just configuring the speed is not enough? Why user needs to know > > the detail and configuration of the lanes? > > Will it work if driver/device configure the "speed x lane" internally > > for the requested speed? > >=20 > > Is there a benefit to force specific lane count for a specific speed > > (like power optimization, just a wild guess)? > >=20 > >=20 > > And +1 for auto-negotiation if possible. >=20 > As you said above,=EF=BC=8Cmultiple lanes work together to achieve desire= d speed. > For example, the following solutions can be used to implement 100G: > 1=E3=80=81Combines four 25G lanes > 2=E3=80=81Combines two 50G lanes > 3=E3=80=81A single 100G lane >=20 > It is assumed that two ports are interconnected and the two ports support > the foregoing three solutions. But, we just configured the speed to 100G = and > one port uses four 25G lanes by default and the other port uses two 50G l= anes > by default, the port cannot be up. In this case, we need to configure the > two ports to use the same solutions (for example, uses two 50G lanes) > so that the ports can be up. Why this config is not OK? How do we know? Really I have a very bad feeling about this feature.