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

["Eads, Gage" <gage.eads@intel.com>]

> -----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.

> 
> >
> > So I think it makes sense to specify the op once at adapter configuration time,
> rather than repeatedly in the datapath. This allows for a cleaner separation of
> configuration and datapath code, and specifying it just once means fewer
> chances to accidentally set the wrong op value.
> >
> > Thanks,
> > Gage