From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id 93A95A0534; Tue, 4 Feb 2020 13:43:10 +0100 (CET) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id AC6FC1C124; Tue, 4 Feb 2020 13:43:09 +0100 (CET) Received: from relay3-d.mail.gandi.net (relay3-d.mail.gandi.net [217.70.183.195]) by dpdk.org (Postfix) with ESMTP id 9F7A21C0D7 for ; Tue, 4 Feb 2020 13:43:08 +0100 (CET) X-Originating-IP: 37.58.153.206 Received: from [10.0.3.185] (bny206.haproxy.com [37.58.153.206]) (Authenticated sender: grive@u256.net) by relay3-d.mail.gandi.net (Postfix) with ESMTPSA id A4B626000F; Tue, 4 Feb 2020 12:43:07 +0000 (UTC) To: Thomas Monjalon , Pavan Nikhilesh Bhagavatula , David Marchand Cc: dev@dpdk.org, Vamsi Krishna Attunuru , Jerin Jacob Kollanukkaran References: <9100295.rMLUfLXkoz@xps> <9b82a6cd-a286-5a5e-7cef-6d16a4355e06@u256.net> <3503128.aV6nBDHxoP@xps> From: Gaetan Rivet Message-ID: Date: Tue, 4 Feb 2020 13:43:07 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.2 MIME-Version: 1.0 In-Reply-To: <3503128.aV6nBDHxoP@xps> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH v7] eal: add manual probing option X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On 04/02/2020 12:07, Thomas Monjalon wrote: > 04/02/2020 11:03, Gaetan Rivet: >> On 03/02/2020 23:21, Thomas Monjalon wrote: >>> 03/02/2020 06:16, Pavan Nikhilesh Bhagavatula: >>>> @David Marchand @thomas@monjalon.net >>>> >>>> Ping? >>>> >>>> Are there any more changes required for this patch? It's been in queue since last October. >>> >>> Sorry we have not decided whether it is a good idea or not. >>> >>> All changes related to probing are very sensitive, >>> and we know a big refactoring would be better than stacking >>> more and more options and corner cases. >>> >>> As we are busy with ABI stability stuff, we did not allocate >>> enough time to properly think about this feature. >>> Please accept our apologies, and let's consider it as >>> a high priority for 20.05 cycle. >>> >> >> Hello Thomas, >> >> This is unfortunate. I pushed Pavan to accept an alternative implementation of this functionality that was less obtrusive, to make the integration smoother. I took care to alleviate those risks from the common path. >> >> The big refactoring is needed yes, but considering the current path I'm not seeing it happen in 20.05. If that means taking this patch as-is in 20.05 for Marvell users, I'm not sure much is gained from waiting 3 months, except minimal risk avoidance. > > > Yes, life is full of bad decisions and consequences. Ah, yes, but I stand by my initial opinion, the first implementation [1] was riskier and less useful. > > I still think there is a risk in adding new user expectations, > and maintaining some code to workaround unknown issues. > > The real question here is to know why this patch? > Is it to workaround a broken driver? > Or to workaround a broken design in EAL and bus drivers? > > Two birds - one stone here: OVS needed a way to disable automatic probing cleanly (current workaround seen in multiple deployment is to add a dummy whitelisted device, which will be ignored by the PCI bus --> it sets the bus in whitelist mode but avoid probing anything), and as a bonus this option allows using devices that depends on other devices being probed already (LAG, representors, failsafe, etc). I'm not sure having a dependent-probe by default is good, and that would be a big change. If we are doing the genesis of this patch, the initial motivation should be asked for more details from Marvell people and David for the OVS side. [1]: First proposal: http://mails.dpdk.org/archives/dev/2019-September/144166.html My arguments: http://mails.dpdk.org/archives/dev/2019-September/144564.html