[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 5:58 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
> 
> 10/07/2017 18:47, Dumitrescu, Cristian:
> > From: Thomas Monjalon [mailto:thomas at monjalon.net]
> > > 10/07/2017 17:46, Dumitrescu, Cristian:
> > > > From: Thomas Monjalon [mailto:thomas at monjalon.net]
> > > > > 10/07/2017 15:21, Dumitrescu, Cristian:
> > > > > > From: Thomas Monjalon [mailto:thomas at monjalon.net]
> > > > > > > 10/07/2017 12:55, Dumitrescu, Cristian:
> > > > > > > > From: Thomas Monjalon [mailto:thomas at monjalon.net]
> > > > > > > > > 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?
> > > > >
> > > > > Not exactly. In my understanding, rte_eth_dev_tm_ops_get() is
> useless.
> > > > > Should it be removed then?
> > > >
> > > > Why do you think it is useless? How would the driver get the function
> > > specific (i.e. rte_flow, rte_tm, ...) operations structure?
> > >
> > > The drivers get the structure via rte_tm_ops_get() function which is
> > > in the well named file rte_tm_driver.h
> > > My question is about rte_eth_dev_tm_ops_get() function which is
> > > in the file rte_ethdev.h.
> > > Please explain the difference between both functions and why
> > > rte_eth_dev_tm_ops_get() is needed.
> > >
> > > Sorry for opening the discussion, I don't see the explanation in doxygen.
> >
> > Hi Thomas,
> >
> > Yes, you're right: drivers get the TM ops structure through the
> rte_tm_ops_get(), which directly accesses the dev_ops. You are fine with
> this, right?
> 
> Yes
> 
> > Your concern is on the rte_eth_dev_tm_ops_get(), right?
> 
> Yes, I feel you start understanding what I'm talking about ;)
> 
> > This function can be used by the app to see if TM feature is supported (the
> ops output argument is non-NULL) or not (the ops output argument is NULL).
> Here we followed the rte_flow pattern. Are you suggesting that we should
> remove it?
> 
> Yes
> As far as I know, the rte_flow API does not expose the ops to the application.
> Can we have the drivers capabilities in a different way?
> In general, capabilities are richer than just checking there
> is a function. I think it is better to have flags.
> Anyway, capabilities API can be discussed after 17.08 merge.

Hi Thomas,

Fixed everything you asked on the next-tm repository, please resume the pull.

I am working to send documentation as separate patch most likely next week. 

Changes:
1. rte_ethdev.[hc]: removed unused function rte_eth_dev_tm_ops_get()
2. doc/api/doxy-api-index.md: removed reference to rte_tm_driver.h
3. rte_tm.h: added EXPERIMENTAL warning at the top of the file
4. MANTAINERS: added EXPERIMENTAL tag for the Traffic Management API
5. Fixed clang warnings due to unused static function

Thanks!

Regards,
Cristian