Re: [dpdk-dev] [PATCH] compressdev: implement API

["Trahe, Fiona" <fiona.trahe@intel.com>]

> -----Original Message-----
> From: Ahmed Mansour [mailto:ahmed.mansour@nxp.com]
> Sent: Friday, March 2, 2018 12:56 AM
> To: Trahe, Fiona <fiona.trahe@intel.com>; Verma, Shally <Shally.Verma@cavium.com>; dev@dpdk.org
> Cc: De Lara Guarch, Pablo <pablo.de.lara.guarch@intel.com>; Athreya, Narayana Prasad
> <NarayanaPrasad.Athreya@cavium.com>; Gupta, Ashish <Ashish.Gupta@cavium.com>; Sahu, Sunila
> <Sunila.Sahu@cavium.com>; Challa, Mahipal <Mahipal.Challa@cavium.com>; Jain, Deepak K
> <deepak.k.jain@intel.com>; Hemant Agrawal <hemant.agrawal@nxp.com>; Roy Pledge
> <roy.pledge@nxp.com>; Youri Querry <youri.querry_1@nxp.com>
> Subject: Re: [dpdk-dev] [PATCH] compressdev: implement API
> 
> On 3/1/2018 9:41 AM, Trahe, Fiona wrote:
> > Hi Shally
> >
> > //snip//
> >> [Shally] This looks better to me. So it mean app would always call xform_init() for stateless and attach
> an
> >> updated priv_xform to ops (depending upon if there's shareable or not). So it does not need to have
> >> NULL pointer on priv_xform. right?
> >>
> > [Fiona] yes. The PMD must return a valid priv_xform pointer.
> 
> [Ahmed] What I understood is that the xform_init will be called once
> initially. if the @flag returned is NONE_SHAREABLE then the application
> must not attach two inflight ops to the same @priv_xform? Otherwise the
> application can attach many ops in flight to the @priv_xform?
[Fiona Yes. App calls the xform_init() once on a device where it plans to send stateless ops.
If PMD returns shareable, then it doesn't need to call again and can attach this to every stateless op going to that device.
If PMD returns SINGLE_OP then it must call xform_init() before every other 
stateless op it wants to have inflight simultaneously. This does not mean it must be called before every op, 
but probably will set up a batch of priv_xforms  - it can reuse each priv_xform once the op finishes with it.