[dpdk-dev] [PATCH V3 1/2] netdev-offload-dpdk: Use has_vlan match attribute
Eli Britstein
elibr at nvidia.com
Tue Aug 24 18:04:41 CEST 2021
On 8/24/2021 6:47 PM, Ilya Maximets wrote:
> External email: Use caution opening links or attachments
>
>
> On 8/24/21 5:25 PM, Eli Britstein wrote:
>> On 8/24/2021 6:08 PM, Finn, Emma wrote:
>>> External email: Use caution opening links or attachments
>>>
>>>
>>> -----Original Message-----
>>> From: Eli Britstein <elibr at nvidia.com>
>>> Sent: Monday 16 August 2021 14:55
>>> To: dev at openvswitch.org; Ilya Maximets <i.maximets at ovn.org>
>>> Cc: Finn, Emma <emma.finn at intel.com>; Stokes, Ian <ian.stokes at intel.com>; Sriharsha Basavapatna <sriharsha.basavapatna at broadcom.com>; Gaetan Rivet <gaetanr at nvidia.com>; Majd Dibbiny <majd at nvidia.com>; Eli Britstein <elibr at nvidia.com>; Salem Sol <salems at nvidia.com>
>>> Subject: [PATCH V3 1/2] netdev-offload-dpdk: Use has_vlan match attribute
>>>
>>> DPDK 20.11 introduced an ability to specify existance/non-existance of VLAN tag by [1].
>>> Use this attribute.
>>>
>>> [1]: 09315fc83861 ("ethdev: add VLAN attributes to ethernet and VLAN items")
>>>
>>> Signed-off-by: Eli Britstein <elibr at nvidia.com>
>>> Reviewed-by: Salem Sol <salems at nvidia.com>
>>>
>>> Hi Eli,
>>>
>>> I tested this but currently we don't have support in the i40e pmd for the has_vlan match attribute and with these patches it is breaking offload for VLAN packets on Intel devices.
>> Hi Emma,
>>
>> Thanks for testing.
>>
>> Is adding such support in your plans?
>>
>> How do you suggest to proceed? It is needed in order to fix OVS bug.
>>
>> Thanks,
>>
>> Eli
> The "Table 1.2 rte_flow items availability in networking drivers"
> here: https://doc.dpdk.org/guides/nics/overview.html
> says that both ixgbe and i40e has a full support for 'vlan' and
> 'eth' items. Is it a bug? Should it be 'partial' instead?
>
> In general, this sounds like a big limitation of rte_flow API.
> I mean the fact that there is no way to get what is implemented by
> a particular driver and what is not implemented in runtime.
> Someone should, probably, work on adding this kind of API to DPDK.
> Otherwise, we will stuck with inability to use certain actions/matches
> unless all the drivers supports them (which is also hard to check
> taking documentation issues into account). If I missed it and the
> API actually exists, we should definitely start using it.
>
> CC: dpdk-dev and rte_flow maintainers.
>
> Thoughts?
There is such an API - rte_flow_validate().
However, in OVS, as each flow is independent and can have different
matches and actions, we just call rte_flow_create(). The PMD (at least
mlx5) first internally validates it (as if rte_flow_validate() is
called), and bail out with a failure in case validate fails.
Can you suggest an effective way to utilize it in OVS?
In theory, if the API exists in rte_flow, OVS should not care if all
PMDs support it or not.
In practice, the "has_vlan" field was introduced only in 20.11, and
apparently Intel has not adapted i40e PMD, so it breaks their offloads.
I suspected this so I've added Emma and Ian to review it.
I don't know i40e HW capabilities, but at least from PMD point of view,
it can be silently ignored until a proper support is added.
>
> Best regards, Ilya Maximets.
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