Question about pattern types for rte_flow RSS rule

[lihuisong (C)]

@Andrew, many thanks for your reply! 😁


在 2022/8/1 22:12, Andrew Rybchenko 写道:
> On 8/1/22 16:27, lihuisong (C) wrote:
>>
>> 在 2022/8/1 19:53, Andrew Rybchenko 写道:
>>> On 8/1/22 06:39, lihuisong (C) wrote:
>>>>
>>>> 在 2022/7/31 17:40, Andrew Rybchenko 写道:
>>>>> Hi, Huisong!
>>>>>
>>>>> On 7/29/22 05:30, lihuisong (C) wrote:
>>>>>> Hi Ori, and all,
>>>>>>
>>>>>> For RSS flow rule, pattern item types and RSS types in action
>>>>>> are an inclusive relationship, and RSS types contain pattern item
>>>>>> types. 
>>>>>
>>>>> I disagree with the statement. We can redirect various packets,
>>>>> but apply RSS on subset only. Everything else goes to the first
>>>>> queue (first entry in the redirection table in fact).
>>>> Sorry, the statement above is inaccurate.
>>>> I mean, pattern item type and RSS types in action are the same for
>>>> creating specified types RSS rule, and this configuration is duplicate
>>>> in this case(in <1> command, I think). Use one of them can specify
>>>> which packet type flow performs action(like <1> or <2> command).
>>>
>>> No, I still disagree. Pattern is about filtering. It defines on which
>>> packets flow rule actions are applied. RSS types choose packet header
>>> fields (if applicable) to calculate hash. I.e. RSS types are no about
>>> filtering.
>>>
>>>>
>>>> Create a RSS rule that redirect ipv4-tcp flow to queues 1 and 2:
>>>> <1> flow create 0 ingress pattern eth / ipv4 / tcp / end actions 
>>>> rss types ipv4-tcp end queues 1 2 end / end
>>>
>>> Yes, this one will redirect IPv4 TCP packets only.
>>>
>>>> <2> flow create 0 ingress pattern end actions rss types ipv4-tcp 
>>>> end queues 1 2 end / end
>>>
>>> The rule will redirect all packets to queues 1 and 2. Some packets will
>>> always go to queue 1, e.g. ARP packets.
>>>
>> In this case, only nonfrag ipv4 TCP packet flow calculate RSS hash 
>> and may
>> distribute to queue 1 and 2 in hardware, and other packets will 
>> always go
>> to queue 1, right?
>
> Yes.
>
>>>> <3> flow create 0 ingress pattern eth / ipv4 / tcp / end actions 
>>>> rss end queues 1 2 end / end
>>>
>>> This one will redirect IPv4 TCP and will use RSS hash function 
>>> specified
>>> in dev_conf on device configuration or default RSS hash function chosen
>>> by corresponding driver.
>>>
>>>>
>>>> What do you think about it, @Andrew and @Ori?
>>>>>
>>>>>> Is it necessary to set pattern item types when specify RSS
>>>>>> types to create a rule? 
>>>>>
>>>>> No, it is not strictly required. It depends on what you want.
>>>>>
>>>>>> How should the user set and how should the
>>>>>> driver do?
>>>>>
>>>>> Pattern and action are not strictly related in the case of RSS.
>>>>> Pattern defines on which packets the rule is applied.
>>>>> Action defines what the rule does. If hash function is not
>>>>> applicable to a packet, e.g. ARP packet and ipv4-tcp hash function,
>>>>> the hash is 0 and goes via redirection table entry 0.
>>>> I know this rule. Ori has already explained the usage of RSS rule 
>>>> in rte_flow API,
>>>> but I still have a confusion momentioned above.
>>>>>
>>>>> Andrew.
>>>>>
>>>>>>
>>>>>> Looking forward to your reply.
>>>>>>
>>>>>> Regards,
>>>>>> Huisong
>>>>>>
>>>>>> 在 2022/7/13 9:34, lihuisong (C) 写道:
>>>>>>> Hi all,
>>>>>>>
>>>>>>> Can someone open my confusion?
>>>>>>> I'm looking forward to your reply.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Huisong.
>>>>>>>
>>>>>>> 在 2022/7/7 11:50, lihuisong (C) 写道:
>>>>>>>> Hi all,
>>>>>>>>
>>>>>>>> From following testpmd command:
>>>>>>>> 'flow create 0 ingress pattern eth / ipv4 / tcp / end actions 
>>>>>>>> rss types ipv4-tcp l3-src-only end queues end / end'
>>>>>>>> and
>>>>>>>> "flow create 0 ingress pattern end actions rss types ipv4-tcp 
>>>>>>>> l3-src-only end queues end / end"
>>>>>>>>
>>>>>>>> I have some confusions about rte_flow RSS rule:
>>>>>>>> 1> Do pattern item types need to set when configure rte_flow 
>>>>>>>> RSS rule?
>>>>>>>> 2> Does the driver need to check and process the pattern? 
>>>>>>>> (After all, the RSS types in actions alreadly contain all RSS 
>>>>>>>> offload types.)
>>>>>>>>
>>>>>>>> Have someone explains it?
>>>>>>>>
>>>>>>>> Regards,
>>>>>>>> Huisong
>>>>>>>>
>>>>>>>> .
>>>>>>> .
>>>>>
>>>>> .
>>>
>>> .
>
> .