From: Olivier Matz <olivier.matz@6wind.com>
To: Shahaf Shuler <shahafs@mellanox.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
"Andrew Rybchenko" <arybchenko@solarflare.com>,
"Bruce Richardson" <bruce.richardson@intel.com>,
"Wang, Haiyue" <haiyue.wang@intel.com>,
"Jerin Jacob Kollanukkaran" <jerinj@marvell.com>,
"Wiles, Keith" <keith.wiles@intel.com>,
"Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
"Morten Brørup" <mb@smartsharesystems.com>,
"Stephen Hemminger" <stephen@networkplumber.org>,
"Thomas Monjalon" <thomas@monjalon.net>
Subject: Re: [dpdk-dev] [PATCH v2] mbuf: support dynamic fields and flags
Date: Thu, 24 Oct 2019 09:07:34 +0200 [thread overview]
Message-ID: <20191024070734.GP25286@glumotte.dev.6wind.com> (raw)
In-Reply-To: <AM0PR0502MB37957D05F0AD18558D40CE67C36A0@AM0PR0502MB3795.eurprd05.prod.outlook.com>
Hi,
On Thu, Oct 24, 2019 at 04:54:20AM +0000, Shahaf Shuler wrote:
> Wednesday, October 23, 2019 4:34 PM, Olivier Matz:
> > Subject: Re: [dpdk-dev] [PATCH v2] mbuf: support dynamic fields and flags
> >
> > Hi Shahaf,
> >
> > On Wed, Oct 23, 2019 at 12:00:30PM +0000, Shahaf Shuler wrote:
> > > Hi Olivier,
> > >
> > > Thursday, October 17, 2019 5:42 PM, Olivier Matz:
> > > > Subject: [dpdk-dev] [PATCH v2] mbuf: support dynamic fields and
> > > > flags
> > > >
> > > > Many features require to store data inside the mbuf. As the room in
> > > > mbuf structure is limited, it is not possible to have a field for
> > > > each feature. Also, changing fields in the mbuf structure can break the
> > API or ABI.
> > > >
> > > > This commit addresses these issues, by enabling the dynamic
> > > > registration of fields or flags:
> > > >
> > > > - a dynamic field is a named area in the rte_mbuf structure, with a
> > > > given size (>= 1 byte) and alignment constraint.
> > > > - a dynamic flag is a named bit in the rte_mbuf structure.
> > > >
> > > > The typical use case is a PMD that registers space for an offload
> > > > feature, when the application requests to enable this feature. As
> > > > the space in mbuf is limited, the space should only be reserved if
> > > > it is going to be used (i.e when the application explicitly asks for it).
> > >
> > > According to description, the dynamic field enables custom application and
> > supported PMDs to use the dynamic part of the mbuf for their specific
> > needs.
> > > However the mechanism to report and activate the field/flag registration
> > comes from the general OFFLOAD flags.
> > >
> > > Maybe it will be better to an option to query and select dynamic fields for
> > PMD outside of the standard ethdev offload flags?
> >
> > It is not mandatory to use the ethdev layer to register a dynamic field or flag
> > in the mbuf. It is just the typical use case.
> >
> > It can also be enabled when using a library that have specific needs, for
> > instance, you call rte_reorder_init(), and it will register the sequence number
> > dynamic field.
> >
> > An application that requires a specific mbuf field can also do the registration
> > by itself.
> >
> > In other words, when you initialize a subpart that needs a dynamic field or
> > flag, you have to do the registration there.
> >
>
> I guess my question mainly targets one of the use cases for dynamic mbuf fields which is vendor specific offloads.
> On such case we would like to have dynamic fields/flags negotiated between the application and PMD.
>
> The question is whether we provide a unified way for application to query PMD specific dynamic fields or we let PMD vendor to implement this handshake as they wish (devargs, through PMD doc, etc..)
I have no strong opinion. It can be a PMD-specific API (function or
devargs) to enable the feature.
The only important thing is to not register the field if it won't be
used.
next prev parent reply other threads:[~2019-10-24 7:07 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-10 9:29 [dpdk-dev] [RFC] " Olivier Matz
2019-07-10 17:14 ` Wang, Haiyue
2019-07-11 7:26 ` Olivier Matz
2019-07-11 8:04 ` Wang, Haiyue
2019-07-11 8:20 ` Olivier Matz
2019-07-11 8:34 ` Wang, Haiyue
2019-07-11 15:31 ` Stephen Hemminger
2019-07-12 9:18 ` Olivier Matz
2019-07-10 17:49 ` Stephen Hemminger
2019-07-10 18:12 ` Wiles, Keith
2019-07-11 7:53 ` Olivier Matz
2019-07-11 14:37 ` Wiles, Keith
2019-07-12 9:06 ` Olivier Matz
2019-07-11 7:36 ` Olivier Matz
2019-07-12 12:23 ` Jerin Jacob Kollanukkaran
2019-07-16 9:39 ` Olivier Matz
2019-07-16 14:43 ` Stephen Hemminger
2019-07-11 9:24 ` Thomas Monjalon
2019-07-12 14:54 ` Andrew Rybchenko
2019-07-16 9:49 ` Olivier Matz
2019-07-16 11:31 ` [dpdk-dev] ***Spam*** " Andrew Rybchenko
2019-09-18 16:54 ` [dpdk-dev] [PATCH] " Olivier Matz
2019-09-21 4:54 ` Wang, Haiyue
2019-09-23 8:31 ` Olivier Matz
2019-09-23 11:01 ` Wang, Haiyue
2019-09-21 8:28 ` Wiles, Keith
2019-09-23 8:56 ` Morten Brørup
2019-09-23 9:41 ` Olivier Matz
2019-09-23 9:13 ` Olivier Matz
2019-09-23 15:14 ` Wiles, Keith
2019-09-23 16:16 ` Olivier Matz
2019-09-23 17:14 ` Wiles, Keith
2019-09-23 16:09 ` Wiles, Keith
2019-10-01 10:49 ` Ananyev, Konstantin
2019-10-17 7:54 ` Olivier Matz
2019-10-17 11:58 ` Ananyev, Konstantin
2019-10-17 12:58 ` Olivier Matz
2019-10-17 14:42 ` [dpdk-dev] [PATCH v2] " Olivier Matz
2019-10-18 2:47 ` Wang, Haiyue
2019-10-18 7:53 ` Olivier Matz
2019-10-18 8:28 ` Wang, Haiyue
2019-10-18 9:47 ` Olivier Matz
2019-10-18 11:24 ` Wang, Haiyue
2019-10-22 22:51 ` Ananyev, Konstantin
2019-10-23 3:16 ` Wang, Haiyue
2019-10-23 10:21 ` Olivier Matz
2019-10-23 15:00 ` Stephen Hemminger
2019-10-23 15:12 ` Wang, Haiyue
2019-10-23 10:19 ` Olivier Matz
2019-10-23 11:45 ` Olivier Matz
2019-10-23 11:49 ` Ananyev, Konstantin
2019-10-23 12:00 ` Shahaf Shuler
2019-10-23 13:33 ` Olivier Matz
2019-10-24 4:54 ` Shahaf Shuler
2019-10-24 7:07 ` Olivier Matz [this message]
2019-10-24 7:38 ` Slava Ovsiienko
2019-10-24 7:56 ` Olivier Matz
2019-10-24 8:13 ` [dpdk-dev] [PATCH v3] " Olivier Matz
2019-10-24 15:30 ` Stephen Hemminger
2019-10-24 15:44 ` Thomas Monjalon
2019-10-24 17:07 ` Stephen Hemminger
2019-10-24 16:40 ` Thomas Monjalon
2019-10-26 12:39 ` [dpdk-dev] [PATCH v4] " Olivier Matz
2019-10-26 17:04 ` Thomas Monjalon
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