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From: Thomas Monjalon <thomas@monjalon.net>
To: Ivan Malov <Ivan.Malov@oktetlabs.ru>,
	Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Cc: dev@dpdk.org, Andy Moreton <amoreton@xilinx.com>,
	orika@nvidia.com, ferruh.yigit@intel.com, olivier.matz@6wind.com
Subject: Re: [dpdk-dev] [PATCH v3 0/5] A means to negotiate delivery of Rx meta data
Date: Fri, 01 Oct 2021 10:11:31 +0200
Message-ID: <5427719.I9DohtKF8S@thomas> (raw)
In-Reply-To: <9f44035b-9569-746a-d2cd-73a793348f31@oktetlabs.ru>

01/10/2021 08:47, Andrew Rybchenko:
> On 9/30/21 10:30 PM, Ivan Malov wrote:
> > Hi Thomas,
> > 
> > On 30/09/2021 19:18, Thomas Monjalon wrote:
> >> 23/09/2021 13:20, Ivan Malov:
> >>> In 2019, commit [1] announced changes in DEV_RX_OFFLOAD namespace
> >>> intending to add new flags, RSS_HASH and FLOW_MARK. Since then,
> >>> only the former has been added. The problem hasn't been solved.
> >>> Applications still assume that no efforts are needed to enable
> >>> flow mark and similar meta data delivery.
> >>>
> >>> The team behind net/sfc driver has to take over the efforts since
> >>> the problem has started impacting us. Riverhead, a cutting edge
> >>> Xilinx smart NIC family, has two Rx prefix types. Rx meta data
> >>> is available only from long Rx prefix. Switching between the
> >>> prefix formats can't happen in started state. Hence, we run
> >>> into the same problem which [1] was aiming to solve.
> >>
> >> Sorry I don't understand what is Rx prefix?
> > 
> > A small chunk of per-packet metadata in Rx packet buffer preceding the
> > actual packet data. In terms of mbuf, this could be something lying
> > before m->data_off.

I've never seen the word "Rx prefix".
In general we talk about mbuf headroom and mbuf metadata,
the rest being the mbuf payload and mbuf tailroom.
I guess you mean mbuf metadata in the space of the struct rte_mbuf?

> >>> Rx meta data (mark, flag, tunnel ID) delivery is not an offload
> >>> on its own since the corresponding flows must be active to set
> >>> the data in the first place. Hence, adding offload flags
> >>> similar to RSS_HASH is not a good idea.
> >>
> >> What means "active" here?
> > 
> > Active = inserted and functional. What this paragraph is trying to say
> > is that when you enable, say, RSS_HASH, that implies both computation of
> > the hash and the driver's ability to extract in from packets
> > ("delivery"). But when it comes to MARK, it's just "delivery". No
> > "offload" here: the NIC won't set any mark in packets unless you create
> > a flow rule to make it do so. That's the gist of it.

OK
Yes I agree RTE_FLOW_ACTION_TYPE_MARK doesn't need any offload flag.
Same for RTE_FLOW_ACTION_TYPE_SET_META.

> >>> Patch [1/5] of this series adds a generic API to let applications
> >>> negotiate delivery of Rx meta data during initialisation period.

What is a metadata?
Do you mean RTE_FLOW_ITEM_TYPE_META and RTE_FLOW_ITEM_TYPE_MARK?
Metadata word could cover any field in the mbuf struct so it is vague.

> >>> This way, an application knows right from the start which parts
> >>> of Rx meta data won't be delivered. Hence, no necessity to try
> >>> inserting flows requesting such data and handle the failures.
> >>
> >> Sorry I don't understand the problem you want to solve.
> >> And sorry for not noticing earlier.
> > 
> > No worries. *Some* PMDs do not enable delivery of, say, Rx mark with the
> > packets by default (for performance reasons). If the application tries
> > to insert a flow with action MARK, the PMD may not be able to enable
> > delivery of Rx mark without the need to re-start Rx sub-system. And
> > that's fraught with traffic disruption and similar bad consequences. In
> > order to address it, we need to let the application express its interest
> > in receiving mark with packets as early as possible. This way, the PMD
> > can enable Rx mark delivery in advance. And, as an additional benefit,
> > the application can learn *from the very beginning* whether it will be
> > possible to use the feature or not. If this API tells the application
> > that no mark delivery will be enabled, then the application can just
> > skip many unnecessary attempts to insert wittingly unsupported flows
> > during runtime.

I'm puzzled, because we could have the same reasoning for any offload.
I don't understand why we are focusing on mark only.
I would prefer we find a generic solution using the rte_flow API.
Can we make rte_flow_validate() working before port start?
If validating a fake rule doesn't make sense,
why not having a new function accepting a single action as parameter?

> Thomas, if I'm not mistaken, net/mlx5 dv_xmeta_en driver option
> is vendor-specific way to address the same problem.

Not exactly, it is configuring the capabilities:
  +------+-----------+-----------+-------------+-------------+
  | Mode | ``MARK``  | ``META``  | ``META`` Tx | FDB/Through |
  +======+===========+===========+=============+=============+
  | 0    | 24 bits   | 32 bits   | 32 bits     | no          |
  +------+-----------+-----------+-------------+-------------+
  | 1    | 24 bits   | vary 0-32 | 32 bits     | yes         |
  +------+-----------+-----------+-------------+-------------+
  | 2    | vary 0-24 | 32 bits   | 32 bits     | yes         |
  +------+-----------+-----------+-------------+-------------+




  reply	other threads:[~2021-10-01  8:11 UTC|newest]

Thread overview: 97+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-02 14:23 [dpdk-dev] [PATCH 0/5] A means to negotiate support for Rx meta information Ivan Malov
2021-09-02 14:23 ` [dpdk-dev] [PATCH 1/5] ethdev: add API " Ivan Malov
2021-09-02 14:47   ` Jerin Jacob
2021-09-02 16:14   ` Kinsella, Ray
2021-09-03  9:34   ` Jerin Jacob
2021-09-02 14:23 ` [dpdk-dev] [PATCH 2/5] net/sfc: provide API to negotiate supported Rx meta features Ivan Malov
2021-09-02 14:23 ` [dpdk-dev] [PATCH 3/5] net/sfc: allow to use EF100 native datapath Rx mark in flows Ivan Malov
2021-09-02 14:23 ` [dpdk-dev] [PATCH 4/5] common/sfc_efx/base: add RxQ flag to use Rx prefix user flag Ivan Malov
2021-09-02 14:23 ` [dpdk-dev] [PATCH 5/5] net/sfc: allow to discern user flag on EF100 native datapath Ivan Malov
2021-09-03  0:15 ` [dpdk-dev] [PATCH v2 0/5] A means to negotiate support for Rx meta information Ivan Malov
2021-09-03  0:15   ` [dpdk-dev] [PATCH v2 1/5] ethdev: add API " Ivan Malov
2021-09-03  0:15   ` [dpdk-dev] [PATCH v2 2/5] net/sfc: provide API to negotiate supported Rx meta features Ivan Malov
2021-09-03  0:15   ` [dpdk-dev] [PATCH v2 3/5] net/sfc: allow to use EF100 native datapath Rx mark in flows Ivan Malov
2021-09-03  0:15   ` [dpdk-dev] [PATCH v2 4/5] common/sfc_efx/base: add RxQ flag to use Rx prefix user flag Ivan Malov
2021-09-03  0:15   ` [dpdk-dev] [PATCH v2 5/5] net/sfc: allow to discern user flag on EF100 native datapath Ivan Malov
2021-09-23 11:20 ` [dpdk-dev] [PATCH v3 0/5] A means to negotiate delivery of Rx meta data Ivan Malov
2021-09-23 11:20   ` [dpdk-dev] [PATCH v3 1/5] ethdev: add API " Ivan Malov
2021-09-30 14:59     ` Ori Kam
2021-09-30 15:07       ` Andrew Rybchenko
2021-09-30 19:07       ` Ivan Malov
2021-10-01  6:50         ` Andrew Rybchenko
2021-10-03  7:42           ` Ori Kam
2021-10-03  9:30             ` Ivan Malov
2021-10-03 11:01               ` Ori Kam
2021-10-03 17:30                 ` Ivan Malov
2021-10-03 21:04                   ` Ori Kam
2021-10-03 23:50                     ` Ivan Malov
2021-10-04  6:56                       ` Ori Kam
2021-10-04 11:39                         ` Ivan Malov
2021-10-04 13:53                           ` Andrew Rybchenko
2021-10-05  6:30                             ` Ori Kam
2021-10-05  7:27                               ` Andrew Rybchenko
2021-10-05  8:17                                 ` Ori Kam
2021-10-05  8:38                                   ` Andrew Rybchenko
2021-10-05  9:41                                     ` Ori Kam
2021-10-05 10:01                                       ` Andrew Rybchenko
2021-10-05 10:10                                         ` Ori Kam
2021-10-05 11:11                                           ` Andrew Rybchenko
2021-10-06  8:30                                             ` Thomas Monjalon
2021-10-06  8:38                                               ` Andrew Rybchenko
2021-10-06  9:14                                                 ` Ori Kam
2021-09-30 21:48     ` Ajit Khaparde
2021-09-30 22:00       ` Ivan Malov
2021-09-30 22:12         ` Ajit Khaparde
2021-09-30 22:22           ` Ivan Malov
2021-10-03  7:05             ` Ori Kam
2021-09-23 11:20   ` [dpdk-dev] [PATCH v3 2/5] net/sfc: support " Ivan Malov
2021-09-23 11:20   ` [dpdk-dev] [PATCH v3 3/5] net/sfc: support flow mark delivery on EF100 native datapath Ivan Malov
2021-09-23 11:20   ` [dpdk-dev] [PATCH v3 4/5] common/sfc_efx/base: add RxQ flag to use Rx prefix user flag Ivan Malov
2021-09-23 11:20   ` [dpdk-dev] [PATCH v3 5/5] net/sfc: report user flag on EF100 native datapath Ivan Malov
2021-09-30 16:18   ` [dpdk-dev] [PATCH v3 0/5] A means to negotiate delivery of Rx meta data Thomas Monjalon
2021-09-30 19:30     ` Ivan Malov
2021-10-01  6:47       ` Andrew Rybchenko
2021-10-01  8:11         ` Thomas Monjalon [this message]
2021-10-01  8:54           ` Andrew Rybchenko
2021-10-01  9:32             ` Thomas Monjalon
2021-10-01  9:41               ` Andrew Rybchenko
2021-10-01  8:55           ` Ivan Malov
2021-10-01  9:48             ` Thomas Monjalon
2021-10-01 10:15               ` Andrew Rybchenko
2021-10-01 12:10                 ` Thomas Monjalon
2021-10-04  9:17                   ` Andrew Rybchenko
2021-10-04 23:50   ` [dpdk-dev] [PATCH v4 0/5] Negotiate the NIC's ability to deliver Rx metadata to the PMD Ivan Malov
2021-10-04 23:50     ` [dpdk-dev] [PATCH v4 1/5] ethdev: negotiate delivery of packet metadata from HW to PMD Ivan Malov
2021-10-05 12:03       ` Ori Kam
2021-10-05 12:50         ` Ivan Malov
2021-10-05 13:17           ` Andrew Rybchenko
2021-10-04 23:50     ` [dpdk-dev] [PATCH v4 2/5] net/sfc: support API to negotiate delivery of Rx metadata Ivan Malov
2021-10-04 23:50     ` [dpdk-dev] [PATCH v4 3/5] net/sfc: support flow mark delivery on EF100 native datapath Ivan Malov
2021-10-04 23:50     ` [dpdk-dev] [PATCH v4 4/5] common/sfc_efx/base: add RxQ flag to use Rx prefix user flag Ivan Malov
2021-10-04 23:50     ` [dpdk-dev] [PATCH v4 5/5] net/sfc: report user flag on EF100 native datapath Ivan Malov
2021-10-05 15:56   ` [dpdk-dev] [PATCH v5 0/5] ethdev: negotiate the NIC's ability to deliver Rx metadata to the PMD Ivan Malov
2021-10-05 15:56     ` [dpdk-dev] [PATCH v5 1/5] ethdev: negotiate delivery of packet metadata from HW to PMD Ivan Malov
2021-10-05 21:40       ` Ajit Khaparde
2021-10-06  6:04         ` Somnath Kotur
2021-10-06  6:10           ` Ori Kam
2021-10-06  7:22             ` Wisam Monther
2021-10-05 15:56     ` [dpdk-dev] [PATCH v5 2/5] net/sfc: support API to negotiate delivery of Rx metadata Ivan Malov
2021-10-05 15:56     ` [dpdk-dev] [PATCH v5 3/5] net/sfc: support flow mark delivery on EF100 native datapath Ivan Malov
2021-10-05 15:56     ` [dpdk-dev] [PATCH v5 4/5] common/sfc_efx/base: add RxQ flag to use Rx prefix user flag Ivan Malov
2021-10-05 15:56     ` [dpdk-dev] [PATCH v5 5/5] net/sfc: report user flag on EF100 native datapath Ivan Malov
2021-10-12 18:08       ` Ferruh Yigit
2021-10-12 19:39         ` Ivan Malov
2021-10-12 19:48         ` Ivan Malov
2021-10-12 19:38   ` [dpdk-dev] [PATCH v6 0/5] ethdev: negotiate the NIC's ability to deliver Rx metadata to the PMD Ivan Malov
2021-10-12 19:38     ` [dpdk-dev] [PATCH v6 1/5] ethdev: negotiate delivery of packet metadata from HW to PMD Ivan Malov
2021-10-12 19:38     ` [dpdk-dev] [PATCH v6 2/5] net/sfc: support API to negotiate delivery of Rx metadata Ivan Malov
2021-10-12 19:38     ` [dpdk-dev] [PATCH v6 3/5] net/sfc: support flow mark delivery on EF100 native datapath Ivan Malov
2021-10-12 19:38     ` [dpdk-dev] [PATCH v6 4/5] common/sfc_efx/base: add RxQ flag to use Rx prefix user flag Ivan Malov
2021-10-12 19:38     ` [dpdk-dev] [PATCH v6 5/5] net/sfc: report user flag on EF100 native datapath Ivan Malov
2021-10-12 19:46   ` [dpdk-dev] [PATCH v7 0/5] ethdev: negotiate the NIC's ability to deliver Rx metadata to the PMD Ivan Malov
2021-10-12 19:46     ` [dpdk-dev] [PATCH v7 1/5] ethdev: negotiate delivery of packet metadata from HW to PMD Ivan Malov
2021-10-12 19:46     ` [dpdk-dev] [PATCH v7 2/5] net/sfc: support API to negotiate delivery of Rx metadata Ivan Malov
2021-10-12 19:46     ` [dpdk-dev] [PATCH v7 3/5] net/sfc: support flow mark delivery on EF100 native datapath Ivan Malov
2021-10-12 19:46     ` [dpdk-dev] [PATCH v7 4/5] common/sfc_efx/base: add RxQ flag to use Rx prefix user flag Ivan Malov
2021-10-12 19:46     ` [dpdk-dev] [PATCH v7 5/5] net/sfc: report user flag on EF100 native datapath Ivan Malov
2021-10-12 23:25     ` [dpdk-dev] [PATCH v7 0/5] ethdev: negotiate the NIC's ability to deliver Rx metadata to the PMD Ferruh Yigit

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