DPDK patches and discussions
 help / color / mirror / Atom feed
From: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
To: Ferruh Yigit <ferruh.yigit@intel.com>, Ori Kam <orika@nvidia.com>,
	Ray Kinsella <mdr@ashroe.eu>, Neil Horman <nhorman@tuxdriver.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
	NBU-Contact-Thomas Monjalon <thomas@monjalon.net>
Subject: Re: [dpdk-dev] [PATCH] doc: announce flow API matching pattern struct changes
Date: Tue, 24 Nov 2020 16:01:40 +0300
Message-ID: <35dccc1c-f388-41b2-6a0e-88b7f8c1c977@oktetlabs.ru> (raw)
In-Reply-To: <44812e16-93b2-81c6-71ed-c2a0e79b9f16@oktetlabs.ru>

On 11/24/20 4:00 PM, Andrew Rybchenko wrote:
> On 11/24/20 3:56 PM, Ferruh Yigit wrote:
>> On 11/24/2020 11:43 AM, Ori Kam wrote:
>>> Hi
>>>
>>>> -----Original Message-----
>>>> From: Ferruh Yigit <ferruh.yigit@intel.com>
>>>> Sent: Monday, November 23, 2020 5:51 PM
>>>> Subject: Re: [PATCH] doc: announce flow API matching pattern struct
>>>> changes
>>>>
>>>> On 11/23/2020 2:25 PM, Andrew Rybchenko wrote:
>>>>> On 11/23/20 5:17 PM, Ferruh Yigit wrote:
>>>>>> On 11/23/2020 1:50 PM, Andrew Rybchenko wrote:
>>>>>>> On 11/23/20 4:40 PM, Ferruh Yigit wrote:
>>>>>>>> Proposing to replace protocol header fields in the
>>>>>>>> ``rte_flow_item_*``
>>>>>>>> structures with the protocol structs, like:
>>>>>>>>
>>>>>>>> Current ``struct rte_flow_item_eth``,
>>>>>>>>
>>>>>>>> struct rte_flow_item_eth {
>>>>>>>>       struct rte_ether_addr dst;
>>>>>>>>       struct rte_ether_addr src;
>>>>>>>>       rte_be16_t type;
>>>>>>>>       uint32_t has_vlan:1;
>>>>>>>>       uint32_t reserved:31;
>>>>>>>> }
>>>>>>>>
>>>>>>>> will become
>>>>>>>>
>>>>>>>> struct rte_flow_item_eth {
>>>>>>>>       struct rte_ether_hdr hdr;
>>>>>>>>       uint32_t has_vlan:1;
>>>>>>>>       uint32_t reserved:31;
>>>>>>>> }
>>>>>>>>
>>>>>>>> This is both for documenting the intention and to be sure
>>>>>>>> ``rte_flow_item_*`` always starts with complete protocol header.
>>>>>>>>
>>>>>>>> Already many ``rte_flow_item_*`` structs implemented to have
>>>>>>>> protocol
>>>>>>>> struct, target is convert all to this usage.
>>>>>>>>
>>>>>>>> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
>>>>>>>
>>>>>>> Acked-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
>>>>>>>
>>>>>>> a minor note below
>>>>>>>
>>>>>>>> ---
>>>>>>>> Cc: Thomas Monjalon <thomas@monjalon.net>
>>>>>>>> Cc: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
>>>>>>>> Cc: Ori Kam <orika@nvidia.com>
>>>>>>>> ---
>>>>>>>>     doc/guides/rel_notes/deprecation.rst | 7 +++++++
>>>>>>>>     1 file changed, 7 insertions(+)
>>>>>>>>
>>>>>>>> diff --git a/doc/guides/rel_notes/deprecation.rst
>>>>>>>> b/doc/guides/rel_notes/deprecation.rst
>>>>>>>> index 96986fabd598..a2fa0c196472 100644
>>>>>>>> --- a/doc/guides/rel_notes/deprecation.rst
>>>>>>>> +++ b/doc/guides/rel_notes/deprecation.rst
>>>>>>>> @@ -88,6 +88,13 @@ Deprecation Notices
>>>>>>>>       will be limited to maximum 256 queues.
>>>>>>>>       Also compile time flag ``RTE_ETHDEV_QUEUE_STAT_CNTRS``
>>>>>>>> will be
>>>>>>>> removed.
>>>>>>>>     +* ethdev: The flow API matching pattern structures, ``struct
>>>>>>>> rte_flow_item_*``,
>>>>>>>> +  should start with relevant protocol header.
>>>>>>>> +  Some matching pattern structures implements this by duplicating
>>>>>>>> protocol header
>>>>>>>> +  fields in the struct. To clarify the intention and to be sure
>>>>>>>> protocol header
>>>>>>>> +  is intact, will replace those fields with relevant protocol
>>>>>>>> header struct.
>>>>>>>> +  Target is v21.02 release and this should not change the ABI.
>>>>>>>> +
>>>>>>>>     * sched: To allow more traffic classes, flexible mapping of
>>>>>>>> pipe
>>>>>>>> queues to
>>>>>>>>       traffic classes, and subport level configuration of pipes and
>>>>>>>> queues
>>>>>>>>       changes will be made to macros, data structures and API
>>>>>>>> functions defined
>>>>>>>>
>>>>>>>
>>>>>>> Just want to highlight that even API could be kept using
>>>>>>> unnamed union for hdr and unnamed structure for existing
>>>>>>> protocol header fields.
>>>>>>>
>>>>>>
>>>>>> Then we may never clean the protocol header fields out of it,
>>>>>> yes this will impact the user but I believe the impact is small and
>>>>>> trivial,
>>>>>> I prefer replacing fields with protocol struct.
>>>>>
>>>>> The problem that API breakages are bad and, for example, OvS uses
>>>>> these
>>>>> fields.
>>>>>
>>>>> May be API breakage should be postponed to 21.11?
>>>>>
>>>>
>>>> Agree but it is not as bad as ABI break, if user is already
>>>> compiling their
>>>> code, it is not too bad to adjust the struct for changes, and the
>>>> changes are
>>>> straightforward.
>>>>
>>> I'm not sure which is worse ABI or API, API is more straight forward
>>> but all apps must be modified,
>>> while ABI is hidden and happens only in rare cases.
>>> In a addition it may result in large number of changes (simple but
>>> large number)
>>>
>>>> But if, somehow, application needs to support multiple version of
>>>> the DPDK it
>>>> can be headache.
>>>>
>>>
>>> Agree,
>>>
>>>> We may go with your suggestion until 21.11, and do the cleanup on
>>>> 21.11, will
>>>> it
>>>> work?
>>> +1 also when considering my next line,
>>>
>>> One more point to consider what happens to struct that are not
>>> according to spec,
>>> for example mpls, geneve where the struct is different than the item.
>>>
>>
>> At least for mpls & geneve, the ABI still looks same so change is
>> still possible, but a few fields seems merged which means the change
>> will require more updates in the user application and the drivers.
>> Anyway, agree to postpone change to the 21.11.
>>
>> I will send a v2.
> 
> I hope it is still possible to add hdr fields without ABI/ABI breakage
> in 20.02.
> 

21.02 of course


  reply	other threads:[~2020-11-24 13:01 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-23 13:40 Ferruh Yigit
2020-11-23 13:50 ` Andrew Rybchenko
2020-11-23 14:17   ` Ferruh Yigit
2020-11-23 14:25     ` Andrew Rybchenko
2020-11-23 15:51       ` Ferruh Yigit
2020-11-24 11:43         ` Ori Kam
2020-11-24 12:56           ` Ferruh Yigit
2020-11-24 13:00             ` Andrew Rybchenko
2020-11-24 13:01               ` Andrew Rybchenko [this message]
2020-11-24 13:15 ` [dpdk-dev] [PATCH v2] " Ferruh Yigit
2020-11-24 14:29   ` Ajit Khaparde
2020-11-27 17:56     ` Thomas Monjalon
2020-11-27 16:16   ` Bruce Richardson

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=35dccc1c-f388-41b2-6a0e-88b7f8c1c977@oktetlabs.ru \
    --to=andrew.rybchenko@oktetlabs.ru \
    --cc=dev@dpdk.org \
    --cc=ferruh.yigit@intel.com \
    --cc=mdr@ashroe.eu \
    --cc=nhorman@tuxdriver.com \
    --cc=orika@nvidia.com \
    --cc=thomas@monjalon.net \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

DPDK patches and discussions

This inbox may be cloned and mirrored by anyone:

	git clone --mirror https://inbox.dpdk.org/dev/0 dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 dev dev/ https://inbox.dpdk.org/dev \
		dev@dpdk.org
	public-inbox-index dev

Example config snippet for mirrors.
Newsgroup available over NNTP:
	nntp://inbox.dpdk.org/inbox.dpdk.dev


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git