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

Jerin Jacob jerinjacobk at gmail.com
Fri May 1 15:18:09 CEST 2020


On Tue, Apr 28, 2020 at 9:24 PM Thomas Monjalon <thomas at monjalon.net> wrote:
>
> 28/04/2020 17:04, Luca Boccassi:
> > On Tue, 2020-04-28 at 15:45 +0100, Bruce Richardson wrote:
> > > On Tue, Apr 28, 2020 at 03:06:20PM +0100, Ferruh Yigit wrote:
> > > > On 4/27/2020 5:59 PM, Jerin Jacob wrote:
> > > > > On Mon, Apr 27, 2020 at 10:19 PM Ferruh Yigit <ferruh.yigit at intel.com> wrote:
> > > > > > On 4/27/2020 5:29 PM, Jerin Jacob wrote:
> > > > > > > On Mon, Apr 27, 2020 at 9:42 PM Ferruh Yigit <ferruh.yigit at intel.com> wrote:
> > > > > > > > On 4/27/2020 10:19 AM, Dumitrescu, Cristian wrote:
> > > > > > > > > From: Yigit, Ferruh <ferruh.yigit at intel.com>
> > > > > > > > > > On 4/24/2020 11:28 AM, Dumitrescu, Cristian wrote:
> > > > > > > > > > > From: Nithin Dabilpuram <nithind1988 at gmail.com>
> > > > > > > > > > > > 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.
> [...]
> > > > > > > > > > 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.
> > > > > > >
> > > > > > > I think, accidentally we can not make a library as NON-experimental.
> > > > > > > TM never went through experimental to mature transition(see git log
> > > > > > > lib/librte_ethdev/rte_tm.h)
> > > > > > > It was a bug to not mark as experimental in each function in the ABI process.
> > > > > > > Some of the features like packet marking are not even implemented by any HW.
> > > > > > > I think, we can make API stable only all the features are implemented
> > > > > > > by one or two HW.
>
> Yes this is what was decided one or two years ago I think.
> But rte_tm API was introduced 3 years ago and is implemented by 6 PMDs.

None of the 6 PMDS covers all the features.

>
> > > > Existing experimental marks are text only for human parsing.
> > > >
> > > > The compiler attribute and build time checks are missing, and the symbol in the
> > > > binary doesn't have experimental tag. Our scripts and automated checks won't
> > > > detect it as experimental.
> > > >
> > > > My point is just having experimental comment in header file is not enough to
> > > > qualify the APIs as experimental.
> > > >
> > > > > Anyway, we need to break the ABI to make it work on various HW.
>
> Yes this is why I was asking in 19.11 to check our API,
> in order to avoid such situation.
>
>
> > > > > I am not sure what to do?
>
> Either manage ABI versioning, or wait 20.11.

ABI change are in structures. So the function versioning does not
help. So we will wait for 20.11 then :-(


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