Re: Question about pattern types for rte_flow RSS rule

["lihuisong (C)" <lihuisong@huawei.com>]

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?
>> <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
>>>>>>
>>>>>> .
>>>>> .
>>>
>>> .
>
> .