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From: Thomas Monjalon <thomas@monjalon.net>
To: Jerin Jacob <jerinjacobk@gmail.com>,
	Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>,
	Ori Kam <orika@nvidia.com>
Cc: Ivan Malov <ivan.malov@arknetworks.am>,
	Ivan Malov <ivan.malov@oktetlabs.ru>,
	Ferruh Yigit <ferruh.yigit@amd.com>,
	Nithin Kumar Dabilpuram <ndabilpuram@marvell.com>,
	Aman Singh <aman.deep.singh@intel.com>,
	Yuying Zhang <yuying.zhang@intel.com>,
	"dev@dpdk.org" <dev@dpdk.org>,
	Hanumanth Reddy Pothula <hpothula@marvell.com>,
	Slava Ovsiienko <viacheslavo@nvidia.com>,
	Jerin Jacob Kollanukkaran <jerinj@marvell.com>,
	"david.marchand@redhat.com" <david.marchand@redhat.com>
Subject: Re: [EXT] Re: [PATCH v5 2/2] app/testpmd: add command to process Rx metadata negotiation
Date: Wed, 01 Feb 2023 10:05:00 +0100	[thread overview]
Message-ID: <3180381.AJdgDx1Vlc@thomas> (raw)
In-Reply-To: <MW2PR12MB4666D916B9F9BBD8C1DA3A77D6D19@MW2PR12MB4666.namprd12.prod.outlook.com>

01/02/2023 10:00, Ori Kam:
> Hi all,
> 
> Sorry for jumping in late,
> 
> > -----Original Message-----
> > From: Jerin Jacob <jerinjacobk@gmail.com>
> > Sent: Wednesday, 1 February 2023 10:53
> > 
> > On Wed, Feb 1, 2023 at 12:46 PM Andrew Rybchenko
> > <andrew.rybchenko@oktetlabs.ru> wrote:
> > >
> > > On 2/1/23 09:10, Ivan Malov wrote:
> > > > Hello everyone,
> > > >
> > > > Since making automatic, or implicit, offload decisions does
> > > > not belong in testpmd responsibility domain, it should be
> > > > safer to avoid calling the "negotiate metadata delivery"
> > > > API with some default selection unless the user asks to
> > > > do so explicitly, via internal CLI or app options.
> > > >
> > > > With that in mind, port config <port_id> ... sounds OK.
> > > >
> > > > PMDs that support flow primitives which can generate metadata
> > > > but, if in started state, can't enable its delivery may pass
> > > > appropriate rte_error messages to the user suggesting
> > > > they enable delivery of such metadata from NIC to PMD
> > > > first. This way, if the person operating testpmd
> > > > enters a flow create command and that fails,
> > > > they can figure out the inconsistency, stop
> > > > the port, negotiate, start and try again.
> > > >
> > > > As for non-debug applications, their developers shall
> > > > be properly informed about the problem of enabling
> > > > delivery of metadata from NIC to PMD. This way,
> > > > they will invoke the negotiate API by default
> > > > in their apps, with the feature selection (eg.
> > > > MARK) as per nature of the app's business.
> > > >
> > > > This API should indeed be helpful to some PMDs with
> > > > regard to collecting upfront knowledge like this.
> > > > At the same time, should be benign to those PMDs
> > > > who do not need this knowledge and can enable
> > > > delivery of metadata right when inserting the
> > > > flow rules. So I hope the API does not create
> > > > too much discomfort to vendors not needing it.
> > > >
> > > > Thank you.
> > > >
> > > > On Wed, 1 Feb 2023, Thomas Monjalon wrote:
> > > >
> > > >> 31/01/2023 17:17, Jerin Jacob:
> > > >>> On Fri, Jan 27, 2023 at 8:31 PM Thomas Monjalon
> > <thomas@monjalon.net>
> > > >>> wrote:
> > > >>>>
> > > >>>> 27/01/2023 11:42, Nithin Kumar Dabilpuram:
> > > >>>>> From: Thomas Monjalon <thomas@monjalon.net>
> > > >>>>>> 27/01/2023 06:02, Nithin Kumar Dabilpuram:
> > > >>>>>>> From: Thomas Monjalon <thomas@monjalon.net>
> > > >>>>>>>> Ferruh is proposing to have a command "port config <port_id>
> > ..."
> > > >>>>>>>> to configure the flags to negotiate.
> > > >>>>>>>> Are you OK with this approach?
> > > >>>>>>>
> > > >>>>>>> Yes, we are fine to have such command to enable and disable the
> > > >>>>>>> feature
> > > >>>>>>> with default being it disabled if supported by PMD.
> > > >>>>>>> Is default being disabled fine if the feature is supported by a
> > > >>>>>>> PMD ?
> > > >>>>>>
> > > >>>>>> I think the default should be enabled for ease of use.
> > > >>>>>
> > > >>>>> Since testpmd is used extensively for benchmarking purposes, we
> > > >>>>> thought it should have minimum features
> > > >>>>> enabled by default. The default testpmd doesn't have any Rx/Tx
> > > >>>>> offloads enabled(except for FAST FREE),  default
> > > >>>>> fwd mode being "iofwd" and the Rx metadata is only referenced
> > when
> > > >>>>> dumping packets.
> > > >>>>>
> > > >>>>>
> > > >>>>>> Do we have similar features disables by default?
> > > >>>>>> I mean do we know features in testpmd which require a "double
> > > >>>>>> enablement"
> > > >>>>>> like one configuration command + one rte_flow rule?
> > > >>>>>
> > > >>>>> Spec itself is that way i.e "RTE_FLOW_RULE +
> > > >>>>> RX_METADATA_NEGOTIATE(once)"
> > > >>>>>
> > > >>>>> Isn't it enough if
> > > >>>>>
> > > >>>>> #1 We have enough print when rte_flow is being create without
> > > >>>>> negotiation done and ask user to enable rx metadata using
> > > >>>>> "port config <port_id>..."
> > > >>>>> #2 Provide testpmd app arg to enable Rx metadata(for example "
> > > >>>>> --rx-metadata") like other features to avoid calling another
> > > >>>>> command before rte flow create.
> > > >>>>
> > > >>>> I'm not sure what is best.
> > > >>>> I will let others discuss this part.
> > > >>>
> > > >>> IMO, enabling something always defeat the purpose to negotiate. IMO,
> > > >>> someone needs to negotiate
> > > >>> for a feature if the feature is needed. I think, the double enablement
> > > >>> is part of the spec itself. In case, The PMD
> > > >>> drivers won't like double enablement, no need to implement the PMD
> > > >>> callback. That way, there is no change in the existing flow.
> > > >>>
> > > >>> The reason why cnxk driver thought of leveraging negotiate() feature
> > > >>> so that it helps for optimization. e.s.p
> > > >>> function template for multiprocess case as we know what features
> > > >>> needed in fastpath upfront.
> > > >>>
> > > >>> If there still concerns with patch we can take up this to TB decide
> > > >>> one way or another to make forward progress. Let us know.
> > > >>
> > > >> Ferruh, Andrew, Ori, Ivan, what is your opinion?
> > > >> Let's progress with this patch to make it in -rc1.
> > >
> > > As I understand all agreed that we need testpmd command to
> > > control negotiated Rx metadata. May be even command-line
> > > option would be useful.
> > >
> > > So, remaining question is what should be the default value in
> > > testpmd. Note that it is just testpmd question since default
> > > value in an abstract application is nothing negotiated
> > > (if I'm not mistaken).
> > >
> > > The key advantaan ge of the current behaviour is to avoid
> > > "double-enabling" in testpmd. It preserves behaviour which
> > > we had before before the API addition. It is a strong
> > > argument. Basically it puts the feature into the same
> > > basket as FAST_FREE - need an action to run faster.
> > 
> > I think, there is a disconnect here. FAST_FREE is enabled by default.
> > i.e We don't need any specific action to run faster. To align with performance
> > test application, by default the configuration should be run faster. User
> > needs to give explicit configuration to allow more offload or the one causes
> > the mpps drops. IMO, That is the theme followed in testpmd.
> > 
> > 
> I agree with Andrew, the default should stay the same, as now, PMD may already implement
> logic to only enable the feature if there is a flow rule.
> Changing the default will result in breaking applications.

That's not what is discussed here.
We are talking only about testpmd default.

> I want to suggest new approach for this feature, 
> maybe we can use the rte_flow_configure, and add a new bit that says if those
> actions are going to be used.
> What do you think?

Let's not change the API please.


> > > I see no problem in such approach.
> > >
> > > The key disadvantage is the difference in testpmd and
> > > other applications default behaviour.
> > >
> > > I'd look at the feature in the following way:
> > > if an application theoretically wants to use
> > > USER_FLAG, USER_MARK or TUNNEL_ID it must negotiate
> > > corresponding Rx metadata to ensure that the feature is
> > > available and HW is informed that application may need it.
> > > Since testpmd supports corresponding flow API actions and
> > > flow tunnels, it tries to negotiate it by default, but do
> > > not fail if the negotiation fails.
> > >
> > > So, I'd would vote to keeping the default value as is.
> > >
> 






  reply	other threads:[~2023-02-01  9:05 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-01  4:41 [PATCH] app/testpmd: add command line argument 'rx-metadata' Hanumanth Pothula
2022-08-01 13:11 ` Hanumanth Pothula
2022-08-01 13:13 ` Hanumanth Pothula
2022-08-01 19:41   ` Ivan Malov
2022-08-02 16:45   ` [PATCH] app/testpmd: add command line argument 'nic-to-pmd-rx-metadata' Hanumanth Pothula
2022-08-02 16:45     ` [PATCH v2 1/2] version: 22.11-rc0 Hanumanth Pothula
2022-08-02 16:45     ` [PATCH v2 2/2] app/testpmd: add command line argument 'nic-to-pmd-rx-metadata' Hanumanth Pothula
2022-08-02 17:51   ` [PATCH v2 1/1] " Hanumanth Pothula
2022-08-30 12:36     ` Hanumanth Reddy Pothula
2022-09-01  8:03     ` Singh, Aman Deep
2022-10-04 14:48       ` Andrew Rybchenko
2022-10-06 18:35     ` [PATCH v3 1/1] app/testpmd: control passing Rx metadata to PMD Hanumanth Pothula
2022-10-17  8:32       ` Andrew Rybchenko
2022-10-27  7:34         ` Thomas Monjalon
2022-10-27 12:54           ` Thomas Monjalon
2022-12-02 16:14             ` [EXT] " Hanumanth Reddy Pothula
2022-12-02 19:41               ` Thomas Monjalon
2022-12-05  7:59                 ` Hanumanth Reddy Pothula
2022-12-05  8:28                   ` Thomas Monjalon
2022-12-05  9:43                     ` Slava Ovsiienko
2022-12-20 20:02       ` [PATCH v4 1/2] ethdev: control Rx metadata negotiation Hanumanth Pothula
2022-12-20 20:02         ` [PATCH v4 2/2] app/testpmd: add command to process " Hanumanth Pothula
2022-12-20 21:23           ` Stephen Hemminger
2022-12-21  2:07         ` [PATCH v5 1/2] ethdev: fix ethdev configuration state on reset Hanumanth Pothula
2022-12-21  2:07           ` [PATCH v5 2/2] app/testpmd: add command to process Rx metadata negotiation Hanumanth Pothula
2023-01-18 10:32             ` Thomas Monjalon
2023-01-19 10:33               ` [EXT] " Hanumanth Reddy Pothula
2023-01-25 12:51                 ` Thomas Monjalon
2023-01-24 18:04             ` Ferruh Yigit
2023-01-25  9:30               ` [EXT] " Hanumanth Reddy Pothula
2023-01-25 12:55                 ` Thomas Monjalon
2023-01-25 13:55                   ` Ferruh Yigit
2023-01-25 13:59                     ` Thomas Monjalon
2023-01-25 14:42                       ` Nithin Kumar Dabilpuram
2023-01-26 11:03                         ` Thomas Monjalon
2023-01-27  5:02                           ` Nithin Kumar Dabilpuram
2023-01-27  8:54                             ` Thomas Monjalon
2023-01-27 10:42                               ` Nithin Kumar Dabilpuram
2023-01-27 15:01                                 ` Thomas Monjalon
2023-01-31 16:17                                   ` Jerin Jacob
2023-01-31 23:03                                     ` Thomas Monjalon
2023-02-01  6:10                                       ` Ivan Malov
2023-02-01  7:16                                         ` Andrew Rybchenko
2023-02-01  8:53                                           ` Jerin Jacob
2023-02-01  9:00                                             ` Ori Kam
2023-02-01  9:05                                               ` Thomas Monjalon [this message]
2023-02-01  9:07                                                 ` Andrew Rybchenko
2023-02-01  9:14                                                   ` Jerin Jacob
2023-02-01  9:29                                                     ` Andrew Rybchenko
2023-02-01 10:48                                                       ` Jerin Jacob
2023-02-01 10:58                                                         ` Andrew Rybchenko
2023-02-01 11:04                                                           ` Thomas Monjalon
2023-02-01 11:15                                                             ` Jerin Jacob
2023-02-01 11:35                                                               ` Ferruh Yigit
2023-02-01 13:48                                                                 ` Jerin Jacob
2023-02-01 14:50                                                                   ` Ferruh Yigit
2023-02-01 15:22                                                                     ` Jerin Jacob
2023-02-02  8:43                                                                       ` Ferruh Yigit
2023-02-02  8:50                                                                         ` Ivan Malov
2023-02-02  9:17                                                                           ` Ferruh Yigit
2023-02-02 10:41                                                                             ` Ivan Malov
2023-02-02 10:48                                                                               ` Ivan Malov
2023-02-02 11:41                                                                                 ` Thomas Monjalon
2023-02-02 11:55                                                                                   ` Ivan Malov
2023-02-02 12:03                                                                                     ` Thomas Monjalon
2023-02-02 12:21                                                                                       ` Andrew Rybchenko
2023-02-01 11:20                                                             ` Ivan Malov
2023-01-25 13:17                 ` Ferruh Yigit
2023-01-25 13:21                   ` Ferruh Yigit
2023-01-25 13:21                 ` Ferruh Yigit
2023-01-16 10:43           ` [PATCH v5 1/2] ethdev: fix ethdev configuration state on reset Hanumanth Reddy Pothula
2023-01-18 10:29           ` Thomas Monjalon
2023-01-24 18:14             ` Ferruh Yigit

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