[dpdk-dev] [PATCH v4 1/4] ethdev: add tm support for shaper config in pkt mode

[Dumitrescu, Cristian]

> -----Original Message-----
> From: Yigit, Ferruh <ferruh.yigit at intel.com>
> Sent: Monday, April 27, 2020 5:13 PM
> To: Dumitrescu, Cristian <cristian.dumitrescu at intel.com>; Nithin Dabilpuram
> <nithind1988 at gmail.com>; Singh, Jasvinder <jasvinder.singh at intel.com>;
> Thomas Monjalon <thomas at monjalon.net>; Andrew Rybchenko
> <arybchenko at solarflare.com>
> Cc: dev at dpdk.org; jerinj at marvell.com; kkanas at marvell.com; Nithin
> Dabilpuram <ndabilpuram at marvell.com>; Kinsella, Ray
> <ray.kinsella at intel.com>; Neil Horman <nhorman at tuxdriver.com>; Luca
> Boccassi <bluca at debian.org>; Kevin Traynor <ktraynor at redhat.com>; David
> Marchand <david.marchand at redhat.com>; Richardson, Bruce
> <bruce.richardson at intel.com>
> Subject: Re: [PATCH v4 1/4] ethdev: add tm support for shaper config in pkt
> mode
> 
> On 4/27/2020 10:19 AM, Dumitrescu, Cristian wrote:
> >
> >
> >> -----Original Message-----
> >> From: Yigit, Ferruh <ferruh.yigit at intel.com>
> >> Sent: Saturday, April 25, 2020 9:09 PM
> >> To: Dumitrescu, Cristian <cristian.dumitrescu at intel.com>; Nithin
> Dabilpuram
> >> <nithind1988 at gmail.com>; Singh, Jasvinder <jasvinder.singh at intel.com>;
> >> Thomas Monjalon <thomas at monjalon.net>; Andrew Rybchenko
> >> <arybchenko at solarflare.com>
> >> Cc: dev at dpdk.org; jerinj at marvell.com; kkanas at marvell.com; Nithin
> >> Dabilpuram <ndabilpuram at marvell.com>
> >> Subject: Re: [PATCH v4 1/4] ethdev: add tm support for shaper config in
> pkt
> >> mode
> >>
> >> On 4/24/2020 11:28 AM, Dumitrescu, Cristian wrote:
> >>>
> >>>
> >>>> -----Original Message-----
> >>>> From: Nithin Dabilpuram <nithind1988 at gmail.com>
> >>>> Sent: Wednesday, April 22, 2020 6:21 PM
> >>>> To: Singh, Jasvinder <jasvinder.singh at intel.com>; Dumitrescu, Cristian
> >>>> <cristian.dumitrescu at intel.com>; Thomas Monjalon
> >>>> <thomas at monjalon.net>; Yigit, Ferruh <ferruh.yigit at intel.com>;
> Andrew
> >>>> Rybchenko <arybchenko at solarflare.com>
> >>>> Cc: dev at dpdk.org; jerinj at marvell.com; kkanas at marvell.com; Nithin
> >>>> Dabilpuram <ndabilpuram at marvell.com>
> >>>> Subject: [PATCH v4 1/4] ethdev: add tm support for shaper config in pkt
> >>>> mode
> >>>>
> >>>> From: Nithin Dabilpuram <ndabilpuram at marvell.com>
> >>>>
> >>>> Some NIC hardware support shaper to work in packet mode i.e
> >>>> shaping or ratelimiting traffic is in packets per second (PPS) as
> >>>> opposed to default bytes per second (BPS). Hence this patch
> >>>> adds support to configure shared or private shaper in packet mode,
> >>>> provide rate in PPS and add related tm capabilities in port/level/node
> >>>> capability structures.
> >>>>
> >>>> This patch also updates tm port/level/node capability structures with
> >>>> exiting features of scheduler wfq packet mode, scheduler wfq byte
> mode
> >>>> and private/shared shaper byte mode.
> >>>>
> >>>> SoftNIC PMD is also updated with new capabilities.
> >>>>
> >>>> Signed-off-by: Nithin Dabilpuram <ndabilpuram at marvell.com>
> >>>> ---
> >>>> v3..v4:
> >>>> - Update text under packet_mode as per Cristian.
> >>>> - Update rte_eth_softnic_tm.c based on Jasvinder's comments.
> >>>> - Add error enum
> >> RTE_TM_ERROR_TYPE_SHAPER_PROFILE_PACKET_MODE
> >>>> - Fix shaper_profile_check() with packet mode check
> >>>> - Fix typo's
> >>>>
> >>>
> >>> Acked-by: Cristian Dumitrescu <cristian.dumitrescu at intel.com>
> >>>
> >>
> >> Hi Nithin,
> >>
> >> It looks like patch is causing ABI break, I am getting following warning [1],
> >> can you please check?
> >>
> >> [1]
> >> https://pastebin.com/XYNFg14u
> >
> >
> > Hi Ferruh,
> >
> > The RTE_TM API is marked as experimental, but it looks that this was not
> correctly marked when __rte_experimental ABI checker was introduced.
> >
> > It is marked as experimental at the top of the rte_tm.h, similarly to other
> APIs introduced around same time, but it was not correctly picked up by the
> ABI check procedure when later introduced, so __rte_experimental was not
> added to every function.
> >
> 
> :(
> 
> Is it time to mature them?
> 
> As you said they are not marked as experimental both in header file
> (function
> declarations) and .map file.
> 
> The problem is, they are not marked as experimental in DPDK_20.0 ABI
> (v19.11),
> so marking them as experimental now will break the ABI. Not sure what to
> do,
> cc'ed a few ABI related names for comment.
> 
> For me, we need to proceed as the experimental tag removed and APIs
> become
> mature starting from v19.11, since this is what happened in practice, and
> remove
> a few existing being experimental references in the doxygen comments.
> 
> Ray, Neil, David, Luca, Kevin, what do you think?

Hi Ferruh,

IMO your proposed approach is fixing the wrong problem and is probably not the right way of doing things.

This API is correctly marked as experimental in the header file rte_tm.h and in the MAINTAINERS file, therefore it should remain experimental, as more changes are expected from the people like Nithin and others currently upstreaming drivers for it.

For some reason, the __rte_experimental tags were not added to this file when the ABI checker was introduced, and this is the real problem that should be fixed.

Regards,
Cristian