Re: [dpdk-dev] [RFC] eventdev: add crypto adapter API header

[Jerin Jacob <jerin.jacob@caviumnetworks.com>]

-----Original Message-----
> Date: Thu, 14 Dec 2017 18:52:02 +0000
> From: "Eads, Gage" <gage.eads@intel.com>
> To: Jerin Jacob <jerin.jacob@caviumnetworks.com>
> CC: "Gujjar, Abhinandan S" <abhinandan.gujjar@intel.com>, "dev@dpdk.org"
>  <dev@dpdk.org>, "Vangati, Narender" <narender.vangati@intel.com>, "Rao,
>  Nikhil" <nikhil.rao@intel.com>, "hemant.agrawal@nxp.com"
>  <hemant.agrawal@nxp.com>, "Doherty, Declan" <declan.doherty@intel.com>,
>  "nidadavolu.murthy@cavium.com" <nidadavolu.murthy@cavium.com>,
>  "nithin.dabilpuram@cavium.com" <nithin.dabilpuram@cavium.com>,
>  "narayanaprasad.athreya@cavium.com" <narayanaprasad.athreya@cavium.com>
> Subject: RE: [RFC] eventdev: add crypto adapter API header
> 
> 
> 
> > -----Original Message-----
> > From: Jerin Jacob [mailto:jerin.jacob@caviumnetworks.com]
> > Sent: Wednesday, December 13, 2017 8:49 PM
> > To: Eads, Gage <gage.eads@intel.com>
> > Cc: Gujjar, Abhinandan S <abhinandan.gujjar@intel.com>; dev@dpdk.org;
> > Vangati, Narender <narender.vangati@intel.com>; Rao, Nikhil
> > <nikhil.rao@intel.com>; hemant.agrawal@nxp.com; Doherty, Declan
> > <declan.doherty@intel.com>; nidadavolu.murthy@cavium.com;
> > nithin.dabilpuram@cavium.com; narayanaprasad.athreya@cavium.com
> > Subject: Re: [RFC] eventdev: add crypto adapter API header
> > 
> > -----Original Message-----
> > > Date: Wed, 13 Dec 2017 23:35:48 +0000
> > > From: "Eads, Gage" <gage.eads@intel.com>
> > > To: Jerin Jacob <jerin.jacob@caviumnetworks.com>, "Gujjar, Abhinandan S"
> > >  <abhinandan.gujjar@intel.com>
> > > CC: "dev@dpdk.org" <dev@dpdk.org>, "Vangati, Narender"
> > >  <narender.vangati@intel.com>, "Rao, Nikhil" <nikhil.rao@intel.com>,
> > > "hemant.agrawal@nxp.com" <hemant.agrawal@nxp.com>, "Doherty, Declan"
> > >  <declan.doherty@intel.com>, "nidadavolu.murthy@cavium.com"
> > >  <nidadavolu.murthy@cavium.com>, "nithin.dabilpuram@cavium.com"
> > >  <nithin.dabilpuram@cavium.com>, "narayanaprasad.athreya@cavium.com"
> > >  <narayanaprasad.athreya@cavium.com>
> > > Subject: RE: [RFC] eventdev: add crypto adapter API header
> > >
> > > Hey Jerin,
> > 
> > Hey Gage,
> > 
> > >
> > > </snip>
> > >
> > > > > +
> > > > > + /**
> > > > > + * @warning
> > > > > + * @b EXPERIMENTAL: this enum may change without prior notice
> > > > > + *
> > > > > + * Crypto event adapter type
> > > > > + */
> > > > > +enum rte_event_crypto_adapter_type {
> > > > > +	RTE_EVENT_CRYPTO_ADAPTER_RX_ONLY = 1,
> > > > > +	/**< Start only Rx part of crypto adapter.
> > > > > +	* Packets dequeued from cryptodev are new to eventdev and
> > > > > +	* events will be treated as RTE_EVENT_OP_NEW */
> > > > > +	RTE_EVENT_CRYPTO_ADAPTER_RX_TX,
> > > > > +	/**< Start both Rx & Tx part of crypto adapter.
> > > > > +	* Packet's event context will be retained and
> > > > > +	* event will be treated as RTE_EVENT_OP_FORWARD */ };
> > > >
> > > > How about leveraging ev.op based schematics as mentioned above?
> > >
> > > That could work, but perhaps the ev.op should be configured once up front, as
> > I see it being a function of the application architecture. A couple possible
> > designs, for example:
> > > - Worker enqueues into cryptodev, adapter polls for response: the adapter
> > port would always use OP_NEW here.
> > > - Worker sends a crypto request event to the adapter, which gives the
> > > request to the cryptodev and polls for response: the adapter port
> > > would always use OP_FWD here. (This ties in with my implicit release
> > > patch (http://dpdk.org/ml/archives/dev/2017-December/083535.html))
> > > - Etc.
> > 
> > Yes. Semantically both approaches will work. I was trying to avoid extra
> > clutter(enum rte_event_crypto_adapter_type) in adapter API.
> > I don't see any problem in moving ev.op to adapter configuration time if it helps
> > the SW driver.
> > 
> > IMO, We can change RTE_EVENT_CRYPTO_ADAPTER_RX_ONLY and
> > RTE_EVENT_CRYPTO_ADAPTER_RX_TX to more appropriate name, something
> > like,
> > RTE_EVENT_CRYPTO_ADAPTER_TYPE_OP_NEW/RTE_EVENT_CRYPTO_ADAPTE
> > R_TYPE_OP_FWD
> > or something like that.
> > 
> 
> I agree that the two naming schemes are equivalent, but since this option would control the adapter's behavior (Rx only vs. Rx + Tx), (IMO) I think Abhinandan's original names do a better job of conveying what effect these two options have on the adapter, compared to the op type names.

The only concern with Rx/Tx terminology was, It is mostly used in the ethdev domain.
In crypto domain, typically, we use enqueue/dequeue.
The only difference between two modes is if adapter enqueue the events with
RTE_EVENT_OP_NEW vs RTE_EVENT_OP_FORWARD then (IMO) we can change
something related to that name to avoid adding a new terminology.

BTW, Based on the earlier discussion, if we need to add opaque eventdev metadata
to cryptodev then it may change ABI.If so, I think, we need to announce
ABI change notice for cryptodev and plan cryptodev adapter for v18.05.