From: Thomas Monjalon <thomas@monjalon.net>
To: Jerin Jacob <jerinjacobk@gmail.com>,
"Dumitrescu, Cristian" <cristian.dumitrescu@intel.com>
Cc: Bruce Richardson <bruce.richardson@intel.com>,
Ferruh Yigit <ferruh.yigit@intel.com>,
Luca Boccassi <bluca@debian.org>,
Nithin Dabilpuram <nithind1988@gmail.com>,
"Singh, Jasvinder" <jasvinder.singh@intel.com>,
Andrew Rybchenko <arybchenko@solarflare.com>,
"dev@dpdk.org" <dev@dpdk.org>,
"jerinj@marvell.com" <jerinj@marvell.com>,
"kkanas@marvell.com" <kkanas@marvell.com>,
Nithin Dabilpuram <ndabilpuram@marvell.com>,
"Kinsella, Ray" <ray.kinsella@intel.com>,
Neil Horman <nhorman@tuxdriver.com>,
Kevin Traynor <ktraynor@redhat.com>,
David Marchand <david.marchand@redhat.com>
Subject: Re: [dpdk-dev] [PATCH v4 1/4] ethdev: add tm support for shaper config in pkt mode
Date: Tue, 28 Apr 2020 17:54:22 +0200 [thread overview]
Message-ID: <1923738.gORTcIGjah@thomas> (raw)
In-Reply-To: <19c8b69f68bcdb7ac23126e63456223f7aff0465.camel@debian.org>
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@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@intel.com> wrote:
> > > > > > > On 4/27/2020 10:19 AM, Dumitrescu, Cristian wrote:
> > > > > > > > From: Yigit, Ferruh <ferruh.yigit@intel.com>
> > > > > > > > > On 4/24/2020 11:28 AM, Dumitrescu, Cristian wrote:
> > > > > > > > > > From: Nithin Dabilpuram <nithind1988@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.
> > > > > Fair enough, specially if the API is not ready yet.
> > > > >
> > > > > But they were part of stable ABI, and marking them as experimental now will
> > > > > break the old applications using these APIs.
> > > >
> > > > it is still marked as EXPERIMENTAL everywhere and API is not ready yet.
rte_tm is implemented in 6 PMDs.
> > > 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.
> > > > IMO, We need to send a patch as Fixes: for the bug of not adding
> > > > __rte_experimental in each function.
No, this is wrong.
> > > Yes, this is where we are, both you and Cristian suggest API is not ready and
> > > should be experimental, but they were part of stable ABI, making them
> > > experimental will break the ABI.
> > > It looks like there is no good option but we should select one of the bad ones.
> > >
> > > > Traffic Management API - EXPERIMENTAL
> > > > M: Cristian Dumitrescu <cristian.dumitrescu@intel.com>
> > > > T: git://dpdk.org/next/dpdk-next-qos
> > > > F: lib/librte_ethdev/rte_tm*
> > > > > > > Ray, Neil, David, Luca, Kevin, what do you think?
> > While I'm not called any of those names, allow me to give my 2c.
> >
> > Since these are marked in binaries as part of the stable ABI, I think we
> > need to honour that for the next two releases 20.05 and 20.08 [which means
> > that we need to put in versioned functions for any changes, not that we
> > can't change anything]
> >
> > For 20.11, I think these should then have one of two options taken:
> > * have these "fixed" and ready to be marked as stable, and officially part
> > of v21 ABI or
> > * mark them as experimental properly, and look to have them as part of the
> > v22 or subsequent ABI
> >
> > Given the comments here, I would tend towards the latter of the above two
> > options, but that's really a decision for the maintainers.
> >
> > Remember, this is not the first bug we have encountered where we messed up
> > some ABI versions in the 19.11 release, and, like the previous one with the
> > screwed up version number, I think we need to honour the ABI committments
> > made, especially since in this case it's only for a few more months till
> > 20.11 development starts.
> >
> > /Bruce
>
> +1
>
> If they are not ready now, they haven't been ready for the past 6
> months either, so staying not ready for 6 more is the lesser evil.
This API is almost 3 years old (release 17.08).
That's good to improve it but we must respect the ABI contract that
we all agreed.
Summary:
17.08: rte_tm is introduced.
17.11: rte_mtr is introduced as experimental, but rte_tm remains stable.
18.02: __rte_experimental tag is introduced (including for rte_mtr),
but rte_tm remains untouched as it is in stable ABI.
19.11: stable ABI is frozen until 20.11
20.05: rte_tm improvement is blocked because of ABI breakage.
It should remind everybody of reviewing the new API and policies,
and maintaining the existing code appropriately.
next prev parent reply other threads:[~2020-04-28 15:54 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-30 16:00 [dpdk-dev] [PATCH 1/2] ethdev: add tm cap for private shaper packet mode Nithin Dabilpuram
2020-03-30 16:00 ` [dpdk-dev] [PATCH 2/2] app/testpmd: add tm non leaf node pktmode command Nithin Dabilpuram
2020-04-07 7:30 ` [dpdk-dev] [PATCH 1/2] ethdev: add tm cap for private shaper packet mode Nithin Dabilpuram
2020-04-07 16:31 ` Dumitrescu, Cristian
2020-04-07 17:21 ` [dpdk-dev] [EXT] " Nithin Dabilpuram
2020-04-10 11:45 ` Dumitrescu, Cristian
2020-04-10 11:56 ` Nithin Dabilpuram
2020-04-11 11:44 ` [dpdk-dev] [PATCH v2 1/4] ethdev: add tm support for shaper config in pkt mode Nithin Dabilpuram
2020-04-11 11:44 ` [dpdk-dev] [PATCH v2 2/4] drivers/net: update tm capability for existing pmds Nithin Dabilpuram
2020-04-11 11:44 ` [dpdk-dev] [PATCH v2 3/4] app/testpmd: add tm cmd for non leaf and shaper pktmode Nithin Dabilpuram
2020-04-11 11:44 ` [dpdk-dev] [PATCH v2 4/4] net/octeontx2: support tm length adjust and pkt mode Nithin Dabilpuram
2020-04-16 13:48 ` [dpdk-dev] [PATCH v2 1/4] ethdev: add tm support for shaper config in " Ferruh Yigit
2020-04-21 5:11 ` [dpdk-dev] [EXT] " Nithin Dabilpuram
2020-04-21 9:30 ` [dpdk-dev] " Dumitrescu, Cristian
2020-04-21 9:58 ` Nithin Dabilpuram
2020-04-21 10:23 ` Dumitrescu, Cristian
2020-04-21 11:55 ` [dpdk-dev] [EXT] " Nithin Dabilpuram
2020-04-22 7:59 ` [dpdk-dev] [PATCH v3] " Nithin Dabilpuram
2020-04-22 7:59 ` [dpdk-dev] [PATCH v3 2/4] drivers/net: update tm capability for existing pmds Nithin Dabilpuram
2020-04-22 7:59 ` [dpdk-dev] [PATCH v3 3/4] app/testpmd: add tm cmd for non leaf and shaper pktmode Nithin Dabilpuram
2020-04-22 7:59 ` [dpdk-dev] [PATCH v3 4/4] net/octeontx2: support tm length adjust and pkt mode Nithin Dabilpuram
2020-04-22 8:09 ` [dpdk-dev] [PATCH v3] ethdev: add tm support for shaper config in " Nithin Dabilpuram
2020-04-22 12:18 ` Singh, Jasvinder
2020-04-22 17:21 ` [dpdk-dev] [EXT] " Nithin Dabilpuram
2020-04-22 10:10 ` [dpdk-dev] " Dumitrescu, Cristian
2020-04-22 11:31 ` [dpdk-dev] [EXT] " Nithin Dabilpuram
2020-04-22 11:49 ` Nithin Dabilpuram
2020-04-22 11:59 ` Dumitrescu, Cristian
2020-04-22 12:01 ` Dumitrescu, Cristian
2020-04-22 8:05 ` [dpdk-dev] [PATCH v3 1/4] " Nithin Dabilpuram
2020-04-22 17:21 ` [dpdk-dev] [PATCH v4 " Nithin Dabilpuram
2020-04-22 17:21 ` [dpdk-dev] [PATCH v4 2/4] drivers/net: update tm capability for existing pmds Nithin Dabilpuram
2020-04-22 17:21 ` [dpdk-dev] [PATCH v4 3/4] app/testpmd: add tm cmd for non leaf and shaper pktmode Nithin Dabilpuram
2020-04-22 17:21 ` [dpdk-dev] [PATCH v4 4/4] net/octeontx2: support tm length adjust and pkt mode Nithin Dabilpuram
2020-04-24 10:28 ` [dpdk-dev] [PATCH v4 1/4] ethdev: add tm support for shaper config in " Dumitrescu, Cristian
2020-04-25 20:09 ` Ferruh Yigit
2020-04-27 9:19 ` Dumitrescu, Cristian
2020-04-27 16:12 ` Ferruh Yigit
2020-04-27 16:28 ` Dumitrescu, Cristian
2020-04-28 15:30 ` Thomas Monjalon
2020-04-28 17:35 ` Dumitrescu, Cristian
2020-04-27 16:29 ` Jerin Jacob
2020-04-27 16:49 ` Ferruh Yigit
2020-04-27 16:59 ` Jerin Jacob
2020-04-28 11:51 ` [dpdk-dev] [EXT] " Nithin Dabilpuram
2020-04-28 13:56 ` Ferruh Yigit
2020-04-28 14:06 ` [dpdk-dev] " Ferruh Yigit
2020-04-28 14:45 ` Bruce Richardson
2020-04-28 15:04 ` Luca Boccassi
2020-04-28 15:54 ` Thomas Monjalon [this message]
2020-04-29 8:45 ` Dumitrescu, Cristian
2020-04-29 9:03 ` Bruce Richardson
2020-05-01 10:27 ` Ferruh Yigit
2020-05-01 13:16 ` [dpdk-dev] [EXT] " Nithin Dabilpuram
2020-08-25 16:59 ` Ferruh Yigit
2020-09-07 11:12 ` Nithin Dabilpuram
2020-09-14 13:01 ` Ferruh Yigit
2020-05-01 13:18 ` [dpdk-dev] " Jerin Jacob
2020-05-05 8:01 ` Ray Kinsella
2020-04-28 15:42 ` Ray Kinsella
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