[dpdk-dev] [pull-request] next-tm 17.08 pre-rc1

[Dumitrescu, Cristian]

> -----Original Message-----
> From: Thomas Monjalon [mailto:thomas at monjalon.net]
> Sent: Monday, July 10, 2017 1:57 PM
> To: Dumitrescu, Cristian <cristian.dumitrescu at intel.com>
> Cc: dev at dpdk.org; jerin.jacob at caviumnetworks.com;
> hemant.agrawal at nxp.com; Singh, Jasvinder <jasvinder.singh at intel.com>;
> Lu, Wenzhuo <wenzhuo.lu at intel.com>; O'Driscoll, Tim
> <tim.odriscoll at intel.com>; Glynn, Michael J <michael.j.glynn at intel.com>;
> Adrien Mazarguil <adrien.mazarguil at 6wind.com>
> Subject: Re: [dpdk-dev] [pull-request] next-tm 17.08 pre-rc1
> 
> Hi,
> 
> 10/07/2017 12:55, Dumitrescu, Cristian:
> > Hi Thomas,
> >
> > From: Thomas Monjalon [mailto:thomas at monjalon.net]
> > >
> > > Hi,
> > >
> > > 04/07/2017 17:38, Cristian Dumitrescu:
> > > >   http://dpdk.org/git/next/dpdk-next-tm
> > >
> > > I'm sorry to not have considered this tree as a high priority.
> > > I think it may be integrated in RC2 because it is a totally new area
> > > and should not break any existing code.
> > >
> > > I prefer to wait because I have seen some things to fix:
> > >
> > > 1/ There is a compilation error with clang (notified in related thread).
> >
> > Thanks for sending the error log, looks simple to fix, we will fix this ASAP.
> >
> > > 2/ Some functions are exposed in the API to query the ops.
> > > It seems dangerous and useless:
> > > 	- rte_eth_dev_tm_ops_get
> > > 	- rte_tm_ops_get
> >
> > Thomas, hopefully this is a misunderstanding on your side :(((.
> 
> Don't worry :)
> 
> > This is a critical point that we debated ad nauseam on this email list (RFC, V1
> -V6) and privately as well. You were included in the conversation, you also
> provided feed-back that we incorporated in the code, as documented in the
> patchset history log.
> >
> > This is simply the mechanism that we (including you) agreed to use for
> modularizing the DPDK ethdev by adding new functionality in a modular plug-
> in way using separate namespace. This is the exact clone of the same
> mechanism that rte_flow is using and was merged in DPDK release 17.02.
> Why this change on the fundamentals now?
> >
> > Hopefully, it is just misunderstanding.
> 
> I mean that only the drivers need to get the ops.
> The applications are using some dedicated functions rte_tm_* , right?
> So the applications does not need direct ops access with
> rte_eth_dev_tm_ops_get()?
> Sorry if it is my misunderstanding.
> 
> About rte_tm_ops_get, I don't remember why I talked about it.
> It seems exposed only to drivers. My mistake. No issue there.
> 

OK, so we're good then?

> > > 3/ The PMD interface file is referenced in the doxygen index:
> > > +  [rte_tm_driver]      (@ref rte_tm_driver.h),
> > > I see that rte_flow_driver.h is also referenced but it seems a mistake.
> >
> > We simply followed the rte_flow precedent. We will remove this line.
> >
> > > 4/ As it is a totally new API, it should be declared as EXPERIMENTAL
> > > in the MAINTAINERS file and in the doxygen.
> >
> > We can add the EXPERIMENTAL tag for this API in the MANTAINERS file and
> at the top of the API file for DPDK release 17.08. Is this OK with you?
> 
> Yes, perfect.
> 
> > But, as Jerin also asked at the time when eventdev API was introduced,
> what is the process to remove the EXPERIMENTAL label? Do you agree that
> we can remove the experimental label in the next release 17.11?
> 
> Yes I think it is reasonnable.
> 
> > IMO it makes sense to mark new APIs as experimental for some time, it
> should be very clear when this label can be removed. We had examples of
> customers being confused by this label and questioning us whether they
> should use such APIs or not, therefore the process or applying & removing
> this label should be clearly documented, which right now it is not at all.
> 
> The idea is to highlight that it is a new API and may be not stable enough.
> The question is when do we know it is mature enough?
> I don't know and I guess it is up to the maintainer of the API.
> Please remind that after removing the EXPERIMENTAL status, you must
> follow
> the API deprecation status.
> 
> > To this moment, this was not followed consistently in DPDK either. Recent
> examples:
> > 1. rte_flow API, introduced in DPDK release 17.02 was never marked as
> EXPERIMENTAL in either MANTAINERS or API file
> > 2. eventdev API, introduced in DPDK release 17.05, was marked as
> EXPERIMENTAL in the MAINTAINERS file, but not in the API file
> 
> Yes, not perfect ;)
> 
> > > 5/ There is no doc in the programmer's guide.
> >
> > We are definitely going to add comprehensive documentation for this new
> API before the 17.08 documentation deadline. Is this OK with you?
> 
> Yes, good to know.
> 
> > As a precedent, eventdev API was introduced in 17.05 with test application
> just added now (one release later).
> >
> > > 6/ There is no application to test it.
> >
> > Yes, we will either extend test-pmd or add a new example application to
> exercise this API for next DPDK release 17.11. CC-ing Tim and Mike to
> confirm.
> 
> Yes I think it would be important to have it in 17.11.
> 
> > > I know that the points 5/ and 6/ are long to complete.
> > > However I would like to know what is the plan?
> > > And should we integrate TM in 17.08 without neither doc nor app?
> >
> > As stated above, we are going to add documentation for this new API on
> this release and test application in the next release.
> 
> OK looks a good plan.
> Please be aware that the documentation must be submitted in two weeks
> to let us few days for reviewing.