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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 3B910C433DF for ; Tue, 13 Oct 2020 15:43:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DC987251F7 for ; Tue, 13 Oct 2020 15:43:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602603805; bh=9H6RvYXjAdfmhiVARIEhYFCwsR6+kod75btIsM3ob0I=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=EVzbDRpUil5EXy+6CiR4ljMohjX7zwHVIynZiWCbPHgYm6gvjDKNpnHL9sggNoQNg Q/8MJ8w8Psp82xVz69SqIgDA4EIfUqJlpLBtHgcPG9nz7J+r9NfJPkB410AnQjTYhu n3bnoqfhjxGnKOk6LTF2RhvB810+Aem51mryuKA0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730623AbgJMPnY (ORCPT ); Tue, 13 Oct 2020 11:43:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:40302 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727830AbgJMPnY (ORCPT ); Tue, 13 Oct 2020 11:43:24 -0400 Received: from kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com (unknown [163.114.132.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DA15B251F1; Tue, 13 Oct 2020 15:43:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602603803; bh=9H6RvYXjAdfmhiVARIEhYFCwsR6+kod75btIsM3ob0I=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=JzcoCzTaABDx4AHinxNLecXKEFgiw8Mpx66MuOnSeUgioP/plxapgXBGvlWDETB0b lyAHI7ExrZu5nF74QtjfPAWQAwlY7RMuCZmX1X5fWaW5Ow76rm/AoUtVolUGbNoBkH LAkrlotQ09Onq+1h42Y2Kli8V01FM5XA/fADoof4= Date: Tue, 13 Oct 2020 08:43:20 -0700 From: Jakub Kicinski To: Danielle Ratson Cc: Ido Schimmel , "netdev@vger.kernel.org" , "davem@davemloft.net" , "Jiri Pirko" , "andrew@lunn.ch" , "f.fainelli@gmail.com" , "mkubecek@suse.cz" , mlxsw , Ido Schimmel , "johannes@sipsolutions.net" Subject: Re: [PATCH net-next 1/6] ethtool: Extend link modes settings uAPI with lanes Message-ID: <20201013084320.40283ba6@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: References: <20201010154119.3537085-1-idosch@idosch.org> <20201010154119.3537085-2-idosch@idosch.org> <20201011153759.1bcb6738@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20201012085803.61e256e6@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, 13 Oct 2020 14:29:29 +0000 Danielle Ratson wrote: > > On Mon, 12 Oct 2020 15:33:45 +0000 Danielle Ratson wrote: > > > > What's the use for this in practical terms? Isn't the lane count > > > > basically implied by the module that gets plugged in? > > > > > > The use is to enable the user to decide how to achieve a certain speed. > > > For example, if he wants to get 100G and the port has 4 lanes, the > > > speed can be achieved it using both 2 lanes of 50G and 4 lanes of 25G, > > > as a port with 4 lanes width can work in 2 lanes mode with double > > > speed each. So, by specifying "lanes 2" he will achieve 100G using 2 > > > lanes of 50G. > > > > Can you give a concrete example of serdes capabilities of the port, what SFP > > gets plugged in and what configuration user wants to select? > > Example: > - swp1 is a 200G port with 4 lanes. > - QSFP28 is plugged in. > - The user wants to select configuration of 100G speed using 2 lanes, 50G each. I mean.. sounds quite contrived to me. But I'm not opposed if others are fine with the change.