From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Monjalon Subject: Re: [PATCH v2 2/6] ethdev: add port ownership Date: Fri, 19 Jan 2018 18:17:51 +0100 Message-ID: <7777073.qS0DmqPron@xps> References: <20180118131017.GA1622@hmswarspite.think-freely.org> <1526278.zylApLv2LJ@xps> <20180119152742.GB9519@hmswarspite.think-freely.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: dev@dpdk.org, Matan Azrad , Bruce Richardson , "Ananyev, Konstantin" , Gaetan Rivet , "Wu, Jingjing" To: Neil Horman Return-path: Received: from out1-smtp.messagingengine.com (out1-smtp.messagingengine.com [66.111.4.25]) by dpdk.org (Postfix) with ESMTP id 1B99D1B2CA for ; Fri, 19 Jan 2018 18:18:28 +0100 (CET) In-Reply-To: <20180119152742.GB9519@hmswarspite.think-freely.org> List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" 19/01/2018 16:27, Neil Horman: > On Fri, Jan 19, 2018 at 03:13:47PM +0100, Thomas Monjalon wrote: > > 19/01/2018 14:30, Neil Horman: > > > So it seems like the real point of contention that we need to settle here is, > > > what codifies an 'owner'. Must it be a specific execution context, or can we > > > define any arbitrary section of code as being an owner? I would agrue against > > > the latter. > > > > This is the first thing explained in the cover letter: > > "2. The port usage synchronization will be managed by the port owner." > > There is no intent to manage the threads synchronization for a given port. > > It is the responsibility of the owner (a code object) to configure its > > port via only one thread. > > It is consistent with not trying to manage threads synchronization > > for Rx/Tx on a given queue. > > > > > Yes, in his cover letter, and I contend that notion is an invalid design point. > By codifying an area of code as an 'owner', rather than an execution context, > you're defining the notion of heirarchy, not ownership. That is to say, > you want to codify the notion that there are top level ports that the > application might see, and some of those top level ports are parents to > subordinate ports, which only the parent port should access directly. If thats > all you want to encode, there are far easier ways to do it: > > struct rte_eth_shared_data { > < existing bits > > struct rte_eth_port_list { > struct rte_eth_port_list *children; > struct rte_eth_port_list *parent; > }; > }; > > > Build an api around a structure like that, so that the parent/child relationship > is globally clear, and this would be much easier, especially if you want to > continue asserting that the notion of synchronization/exclusion is an exercise > left to the application. Not only Neil. An owner can be something else than a port. An owner can be an app process (multi-processes). An owner can be a library. The intent is really to solve the generic problem of which code is managing a port.