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 A4793A04C2; Mon, 25 Nov 2019 11:44:31 +0100 (CET) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 320C92952; Mon, 25 Nov 2019 11:44:30 +0100 (CET) Received: from mail-io1-f68.google.com (mail-io1-f68.google.com [209.85.166.68]) by dpdk.org (Postfix) with ESMTP id B3331A3 for ; Mon, 25 Nov 2019 11:44:28 +0100 (CET) Received: by mail-io1-f68.google.com with SMTP id b26so13743942ion.7 for ; Mon, 25 Nov 2019 02:44:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=v4v+vRChbzMsXJEqQzSXY0lOIhUqMr2Ch5y2oMLVJC8=; b=FwRSG3ihs+cEynh2KL+84bm7j/xEIRZX52IkufWk6JDOfgpV8tV4vX06bQdNXBEAqN ONdUW1mY2DkPTaZujiwHxunHeDjYasgHxf3AUOXIJ4TKeMwSBqyNJiCSR46nLvo/whHr hDzsFJFmeCJWaButj3BHv2KjlfzbV8keEqM2rkcJGW+s1Ugl/TxGh8W3/qmYlqpGnJRU DtsvCYpKGioUlgxpPftrO0Dyqq3UFqlBH4Ob1mD0oNPxSOBVLqMkF/j5izB/PW4hjBP9 2j1iUmMjPXZefRIg9Gvl+dx4sTOs7zSRLFcVXfw6nlCDh75v4SUky4BYmb2a1wrY9zAy sisQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=v4v+vRChbzMsXJEqQzSXY0lOIhUqMr2Ch5y2oMLVJC8=; b=qVdN6svje+Z1Ls0a61JfWOJrcMclV8pxflDx4lL0zGldPgf00jIkU41KDklAowM0aC o5YmTTT+wLMcFadX0SBc+mvO630CTIYjpPLeOHkdYZ/QH2/F+uVCIA9NDL0jCPLb2Aby mRR5o3+R4BpOfAwJYSyf0lSdRdbNhL0j1k9/N9oGWLtYMtL7On3FQLXzL0IP9hRvFAtu P44n/vPb4w0hDPhPdOt5COZ/ZkkO+RtWuaLjYHdp10z+6jV8HGqJVD79qs5QLjzPNnjp MSeK8ybiFcbJPHIAcJooL0OYNJZU+R4Nvnc5/y8M0YpI+wAvZPILgdGTRISmSfq2xxWx 1rzw== X-Gm-Message-State: APjAAAUIBou5Lxz327wwRRLI4fv7m8Xg5DHoOQPGVKpz8z479y70Tvkt jcnkLRjIoAG8hpP4UR5aY5QhiDkXIFgeljThyHA= X-Google-Smtp-Source: APXvYqwamUjelzvk+x9WjY0B9DfwcEcnuKXEOym598+FhcDFoQhMxoglgEiT/Hr++IlKo8I2uHVTdj4ZIMdoDetGlq4= X-Received: by 2002:a6b:7f03:: with SMTP id l3mr13947852ioq.271.1574678667465; Mon, 25 Nov 2019 02:44:27 -0800 (PST) MIME-Version: 1.0 References: <1574165145-23960-1-git-send-email-arybchenko@solarflare.com> <4645183.OkDat4SStM@xps> <13121897.9FIjf2LrnR@xps> In-Reply-To: <13121897.9FIjf2LrnR@xps> From: Jerin Jacob Date: Mon, 25 Nov 2019 19:44:11 +0900 Message-ID: To: Thomas Monjalon Cc: Andrew Rybchenko , Ferruh Yigit , Pavan Nikhilesh , Neil Horman , John McNamara , Marko Kovacevic , dpdk-dev , Ori Kam , David Marchand , Olivier Matz , "Ananyev, Konstantin" Content-Type: text/plain; charset="UTF-8" Subject: Re: [dpdk-dev] [PATCH v2 3/3] ethdev: improve flow mark Rx offload deprecation notice 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 Sun, Nov 24, 2019 at 3:12 AM Thomas Monjalon wrote: > > 23/11/2019 10:42, Jerin Jacob: > > On Sat, Nov 23, 2019 at 3:58 AM Thomas Monjalon wrote: > > > 22/11/2019 12:53, Andrew Rybchenko: > > > > On 11/22/19 2:15 PM, Thomas Monjalon wrote: > > > > > 22/11/2019 11:12, Andrew Rybchenko: > > > > >> On 11/22/19 1:01 AM, Thomas Monjalon wrote: > > > > >>> 19/11/2019 13:12, Andrew Rybchenko: > > > > >>>> The deprecation notice is required since it adds more requirements > > > > >>>> when RTE flow mark and flag actions may be used and require > > > > >>>> changes in applications. > > > > >>> I am still not sure what is the best solution here. > > > > >>> I continued to think about it in this thread: > > > > >>> http://mails.dpdk.org/archives/dev/2019-November/151960.html > > > > >>> > > > > >>> I think we cannot require any application change until 20.11 > > > > >>> in order to keep API (and behaviour) compatibility. > > > > >> Expected, but still very disappointing. > > > > >> > > > > >> The feature is implemented by Pavan (@ Marvell), supported by me, > > > > >> used by Qi (@ Intel), looks better than alternatives from application > > > > >> developer point of view [1] and finally postponed for 1 year without really > > > > >> strong motivation. > > > > > > > > > > I see different valuable point of views. This is enough motivation. > > > > > > > > It looks like I miss it in previous discussion, I would be thankful if > > > > you give me links to read or hints how to find. > > > > > > http://mails.dpdk.org/archives/dev/2019-November/150793.html > > > > > > > Introducing new types of controls would make configuration more and > > > > more complex. I think that many different types of control would > > > > over-complicate it. May be it is unavoidable, but it should be clear > > > > why the problem cannot be solved using existing types of controls > > > > (e.g. offloads). > > > > > > The offload control is used as an effective configuration for now. > > > The features which are configured with DEV_RX_OFFLOAD_* > > > do not need any other API to be used. > > > Extending DEV_RX_OFFLOAD_* bits for enabling features which > > > must be configured via other API anyway, is possible. > > > The real problem is that features in DEV_RX_OFFLOAD_* are supposed > > > to be disabled by default. If we add some opt-in features here, > > > we cannot enable them by default for API compatibility and do the > > > right thing by default. > > > > > > Choosing DEV_RX_OFFLOAD_* bits or rte_eth_dev_opt* functions is a detail. > > > The real decision is to change the API for using all these features. > > > Can we keep all features available by default (opt-out)? > > > > IMO, *rte_eth_dev_opt* has following problems > > > > 1) It is not multi-process friendly. If we are changing the Rx/Tx > > function pointer, based on > > the selected offload, then, using *rte_eth_dev_opt* scheme won't > > really work(if the new API > > called after the secondary process launch) > > Yes it must be used before launching the secondary process. > It is the same as DEV_RX_OFFLOAD_* config. Yes. rte_eth_dev_opt_* has another dimension to enable and disable as API. So, we need to document, opt-in -> start() -> opt-out case won't work in multi process case. > > > 2) If we are taking rte_eth_dev_opt path then by default feature has > > to be enabled to > > not break the functional ABI. That scheme won't scale if as when we > > keep adding the new features. > > It is always easy for the application to define "what it wants" vs > > "what it does not want" > > Yes, opt-in may look more natural than opt-out. > But opt-in makes the default more complex, and changes the API. > > > 3) Defining the device state after the reconfigure operation. > > > > IMO, if any operation is connected to fastpath it is better to use > > DEV_RX_OFFLOAD_ like > > this feature where enable or disable PMDs from updating > > ``rte_mbuf::hash::fdir`` so that if possible > > we can use different Rx function pointer if possible(Hence it can work > > with the multi-process case case) > > I reply to 2 and 3 together. > > We decided that offloads must be disabled by default. > This is what we have in 19.11: > - Some offloads are enabled before start with DEV_?X_OFFLOAD_* > - Some offloads are enabled with functions at any time > > For the second type of offloads, you want to know, before start, > whether it will be used or not. > If adding the second type of offloads (like rte_flow ones) > to DEV_?X_OFFLOAD_*, it means it must be enabled 2 times: > - before start with offload bits > - later with more precise functions > > I would like to avoid changing the default behaviour, > which is to enable an offload only one time. > That's why I think this second category of offloads should > offer opt-out (global disabling), so it will continue > to work by default if they are configured. > > I hope you understand the difference between the two categories. I understand the difference. The only point of "difference in opinion" is the default behavior of the feature/offload. If it is in RX_OFFLOAD scheme then by default it is disabled. opt_* scheme makes this new feature/offload enabled default to avoid changing the default behavior. It is good to avoid functional ABI change. But bad as, 1) New API starts bloating the ethdev API. 2) It is diffcult for application guys to figure out what are features need to be disabled to performance as he/she does not know, for the given release, the enabled features. Item (1) is a trade-off between elegance vs ABI compatibility. No strong opinion on this. To fix the item (2), Can we get have an API in ethdev to get enabled features so that the application can probe and disable if required? For example, rte_eth_dev_set_ptypes() comes in same category, By default, ptype parsing is enabled. I think, we can have a general interface to "probe" the by default enabled features and disable it if required. Not scattered API for each feature. The above scheme fixe my concerns. Thoughts? > For now, it looks I failed to explain it clearly enough. No, the explanation is very clear. > >