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,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 A5343C433DB for ; Mon, 18 Jan 2021 13:09:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7533A22227 for ; Mon, 18 Jan 2021 13:09:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392080AbhARNCg (ORCPT ); Mon, 18 Jan 2021 08:02:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34740 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391972AbhARNA4 (ORCPT ); Mon, 18 Jan 2021 08:00:56 -0500 Received: from mail-wr1-x42b.google.com (mail-wr1-x42b.google.com [IPv6:2a00:1450:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3245CC061573 for ; Mon, 18 Jan 2021 05:00:14 -0800 (PST) Received: by mail-wr1-x42b.google.com with SMTP id d26so16363832wrb.12 for ; Mon, 18 Jan 2021 05:00:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=resnulli-us.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=4qPAUXos/RFVlktxv/aD1QceJ4yoWahYlcZ36hAfgtY=; b=ZbAaW3iarMkSzWxsa5oUIsBzwxb3iFZIeqpAnVqC++nNNjhwUjeR6sJvFUT0gEY67V dIkfPnbCmPARJTI4ScWAM9mRF/XKYHfYqyanRx5VHHAxZTaTHAVxY/ehEJoj+ZA8Oftx U5eqlcBcwtX+aE5ipWmspLjKYd18ZrnALIVicsgGADwjqLK6c3/zOpdA0Ih4rDgjkNk9 /CYoqd0QdZkVZhEkVC1Q4DWh3hYraqIL7NLCBxXaLapSoug8eCHSXd6ADYP5gSsNIvm6 vbTeYUNeNO1g6Wz/6YajALGyF9IdCJlBsf2w3154RMs+Jg7cdJy3eK2oidSg5xjZn/IC i3rg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=4qPAUXos/RFVlktxv/aD1QceJ4yoWahYlcZ36hAfgtY=; b=qTRRs/kX94lw0HIClDpxAIP4UrofLjspu8+ETL8h+sRZ0iAD/URdJXeRS06RPopu0r BO8pBicJ2qMXoHIhHV+qaW7OSRMFSo9qAgahoDNEnXal/hwE92gb/vlzsudDDAxpHsi+ oTrDV3vzoVtCCg9JswaJTj4CqO/DKJMIGyySD4gA/qSJ4721thiBh0wI0YSBt9ZVvKFd S+W9uaxGNADB6pPZ2COZPqGri/xyaiEj9yRtgU/+YPtSlnROa9GoRJCTtueNAO3pg2Am GMRcfkMtFeOZMFZJssh2vHtruMQtBRj0OcQqOg5Xm3i4KkK2BhWPaNias0ksf/f3ONKo BiHA== X-Gm-Message-State: AOAM530xkYxSaCImIrOaW6lST4GNXXpmZ+l/25uLk8cxk/fjj2rVaYIU l3Dvtsksv7Un64R4aIeJBrZMlA== X-Google-Smtp-Source: ABdhPJzxOZaozYJ+eQGCyS2ZJQ24T0rOg6s+pR5uPrAJeXMwawBq/dapFX+hyHZInjZgJkkM19UnfQ== X-Received: by 2002:adf:e710:: with SMTP id c16mr25993307wrm.295.1610974812807; Mon, 18 Jan 2021 05:00:12 -0800 (PST) Received: from localhost ([85.163.43.78]) by smtp.gmail.com with ESMTPSA id r126sm11768814wma.48.2021.01.18.05.00.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Jan 2021 05:00:12 -0800 (PST) Date: Mon, 18 Jan 2021 14:00:09 +0100 From: Jiri Pirko To: Jakub Kicinski Cc: netdev@vger.kernel.org, davem@davemloft.net, jacob.e.keller@intel.com, roopa@nvidia.com, mlxsw@nvidia.com Subject: Re: [patch net-next RFC 00/10] introduce line card support for modular switch Message-ID: <20210118130009.GU3565223@nanopsycho.orion> References: <20210113121222.733517-1-jiri@resnulli.us> <20210113182716.2b2aa8fa@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20210114074804.GK3565223@nanopsycho.orion> <20210114153013.2ce357b0@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20210115143906.GM3565223@nanopsycho.orion> <20210115112617.064deda8@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210115112617.064deda8@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Fri, Jan 15, 2021 at 08:26:17PM CET, kuba@kernel.org wrote: >On Fri, 15 Jan 2021 15:39:06 +0100 Jiri Pirko wrote: >> >I'm not a SFP experts so maybe someone will correct me but AFAIU >> >the QSFP (for optics) is the same regardless of breakout. It's the >> >passive optical strands that are either bundled or not. So there is >> >no way for the system to detect the cable type (AFAIK). >> >> For SFP module, you are able to detect those. > >Not sure you understand what I'm saying. Maybe you're thinking about >DACs? This is a optical cable for breakout: > >https://www.fs.com/products/68048.html > >There is no electronics in it to "detect" things AFAIU. Same QSFP can >be used with this cable or a non-breakout. Ah, got you. > >> >Or to put it differently IMO the netdev should be provisioned if the >> >system has a port into which user can plug in a cable. When there is >> >> Not really. For slit cables, the ports are provisioned not matter which >> cable is connected, slitter 1->2/1->4 or 1->1 cable. >> >> >> >a line card-sized hole in the chassis, I'd be surprised to see ports. >> > >> >That said I never worked with real world routers so maybe that's what >> >they do. Maybe some with a Cisco router in the basement can tell us? :) >> >> The need for provision/pre-configure splitter/linecard is that the >> ports/netdevices do not disapper/reappear when you replace >> splitter/linecard. Consider a faulty linecard with one port burned. You >> just want to replace it with new one. And in that case, you really don't >> want kernel to remove netdevices and possibly mess up routing for >> example. > >Having a single burned port sounds like a relatively rare scenario. Hmm, rare in scale is common... >Reconfiguring routing is not the end of the world. Well, yes, but you don't really want netdevices to come and go then you plug in/out cables/modules. That's why we have split implemented as we do. I don't understand why do you think linecards are different. Plus, I'm not really sure that our hw can report the type, will check. One way or another, I think that both configuration flows have valid usecase. Some user may want pre-configuration, some user may want auto. Btw, it is possible to implement splitter cable in auto mode as well. > >> >If the device really needs this configuration / can't detect things >> >automatically, then we gotta do something like what you have. >> >The only question is do we still want to call it a line card. >> >Sounds more like a front panel module. At Netronome we called >> >those phymods. >> >> Sure, the name is up to the discussion. We call it "linecard" >> internally. I don't care about the name. > >Yeah, let's call it something more appropriate to indicate its >breakout/retimer/gearbox nature, and we'll be good :) Well, it can contain much more. It can contain a smartnic/fpga/whatever for example. Not sure we can find something that fits to all cases. I was thinking about it in the past, I think that the linecard is quite appropriate. It connects with lines/lanes, and it does something, either phy/gearbox, or just interconnects the lanes using smartnic/fpga for example.