Re: [PATCH v3 1/6] doc: add RSS hash algorithm feature

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

在 2023/11/28 18:09, Ferruh Yigit 写道:
> On 11/28/2023 1:21 AM, lihuisong (C) wrote:
>> 在 2023/11/27 23:43, Ferruh Yigit 写道:
>>> On 11/27/2023 1:12 PM, lihuisong (C) wrote:
>>>> 在 2023/11/27 20:19, Ferruh Yigit 写道:
>>>>> On 11/25/2023 1:47 AM, Huisong Li wrote:
>>>>>> Add hash algorithm feature introduced by 23.11 and fix some RSS
>>>>>> features
>>>>>> description.
>>>>>>
>>>>>> Fixes: 34ff088cc241 ("ethdev: set and query RSS hash algorithm")
>>>>>>
>>>>>> Signed-off-by: Huisong Li <lihuisong@huawei.com>
>>>>>> Acked-by: Chengwen Feng <fengchengwen@huawei.com>
>>>>>> ---
>>>>>>     doc/guides/nics/features.rst | 26 ++++++++++++++++++++++----
>>>>>>     1 file changed, 22 insertions(+), 4 deletions(-)
>>>>>>
>>>>>> diff --git a/doc/guides/nics/features.rst
>>>>>> b/doc/guides/nics/features.rst
>>>>>> index 1a1dc16c1e..0d38c5c525 100644
>>>>>> --- a/doc/guides/nics/features.rst
>>>>>> +++ b/doc/guides/nics/features.rst
>>>>>> @@ -277,10 +277,12 @@ RSS hash
>>>>>>     Supports RSS hashing on RX.
>>>>>>       * **[uses]     user config**: ``dev_conf.rxmode.mq_mode`` =
>>>>>> ``RTE_ETH_MQ_RX_RSS_FLAG``.
>>>>>> -* **[uses]     user config**: ``dev_conf.rx_adv_conf.rss_conf``.
>>>>>> +* **[uses]     user config**: ``rss_conf.rss_hf``.
>>>>>>
>>>>> Feature title is "RSS hash", it can be two things,
>>>>> 1. "Receive Side Scaling" support
>>>>> 2. Provide RSS hash to application
>>>>>
>>>>> When this document first prepared RSS hash value was always provided to
>>>>> the application when RSS enabled.
>>>>> So intention with this feature was "Receive Side Scaling" support,
>>>>> hence
>>>>> 'RTE_ETH_MQ_RX_RSS_FLAG' added.
>>>>>
>>>>> Later providing RSS has to the application separated as optimization,
>>>>> 'RTE_ETH_RX_OFFLOAD_RSS_HASH' & 'RTE_MBUF_F_RX_RSS_HASH' added for this
>>>>> support.
>>>> What should I do for above two comments？
>>>> To tell application how to use it?
>>>>
>>> Just tried to give some context.
>> got it.
>>>   
>>>
>>>>> As the intention of this feature is "Receive Side Scaling" support, we
>>>>> shouldn't reduce configuration struct to 'rss_conf.rss_hf'.
>>>>>
>>>>> Instead perhaps can expand to:
>>>>> 'rte_eth_conf.rx_adv_conf.rss_conf', 'rte_eth_rss_conf'
>>>>    I just pick their common part.😁
>>>>
>>>> ok, will fix it.
>>>>
>>>>>>     * **[uses]     rte_eth_rxconf,rte_eth_rxmode**:
>>>>>> ``offloads:RTE_ETH_RX_OFFLOAD_RSS_HASH``.
>>>>>>     * **[provides] rte_eth_dev_info**: ``flow_type_rss_offloads``.
>>>>>>     * **[provides] mbuf**: ``mbuf.ol_flags:RTE_MBUF_F_RX_RSS_HASH``,
>>>>>> ``mbuf.rss``.
>>>>>> +* **[related]  API**: ``rte_eth_dev_configure``,
>>>>>> ``rte_eth_dev_rss_hash_update``
>>>>>> +  ``rte_eth_dev_rss_hash_conf_get()``.
>>>>>>     
>>>>> ack
>>>>>
>>>>>>       .. _nic_features_inner_rss:
>>>>>> @@ -288,7 +290,7 @@ Supports RSS hashing on RX.
>>>>>>     Inner RSS
>>>>>>     ---------
>>>>>>     -Supports RX RSS hashing on Inner headers.
>>>>>> +Supports RX RSS hashing on Inner headers by rte_flow API.
>>>>>>     
>>>>> This should be clarified with details below, not sure if it required to
>>>>> limit description to rte_flow.
>>>> But this block like rte_flow_action_rss is from rte_flow.
>>>> And ethdev ops doesn't support inner RSS.
>>>> So I think it is ok.
>>>>
>>> Yes it is supported by rte_flow, and '[uses]' information should already
>>> clarify it.
>> Should we remove the 'rte_flow API' wrods I added in above description?
>>
> I think it can be removed.
The latest version(V5, only three fix doc patch) has been sent out.
Do we I need to send V6 for this?😂
>
>
>>>>> And I guess similar confusion exist with the providing hash to user.
>>>>> Need to check if rte_flow implementation puts hash to mbuf along with
>>>>> doing the RSS, or if it checks 'RTE_ETH_RX_OFFLOAD_RSS_HASH' offload,
>>>>> and update below items accordingly.
>>>> Do we need to tell user how to use it here?
>>>> I feel this document is a little simple and main to list interface for
>>>> user.
>>>> In addition, it is better that the more detail about RSS should be
>>>> presented  in rte_flow features.
>>>>
>>> No, I am not suggesting to add more detail.
>>>
>>> My concern is 'RTE_ETH_RX_OFFLOAD_RSS_HASH' information may not be
>>> correct, ethdev APIs checks offload flags, but does rte_flow
>>> implementation check it?
>> As far as I know, It is possibly verified in PMD if have or required.
>>> My suggestion is double check that piece of information and fix it if
>>> required.
>>>
>>>
>>>>>>     * **[uses]    rte_flow_action_rss**: ``level``.
>>>>>>     * **[uses]    rte_eth_rxconf,rte_eth_rxmode**:
>>>>>> ``offloads:RTE_ETH_RX_OFFLOAD_RSS_HASH``.
>>>>>> @@ -303,9 +305,25 @@ RSS key update
>>>>>>     Supports configuration of Receive Side Scaling (RSS) hash
>>>>>> computation. Updating
>>>>>>     Receive Side Scaling (RSS) hash key.
>>>>>>     -* **[implements] eth_dev_ops**: ``rss_hash_update``,
>>>>>> ``rss_hash_conf_get``.
>>>>>> +* **[implements] eth_dev_ops**: ``dev_configure``,
>>>>>> ``rss_hash_update``, ``rss_hash_conf_get``.
>>>>>> +* **[uses]     user config**: ``rss_conf.rss_key``,
>>>>>> ``rss_conf.rss_key_len``
>>>>>>     * **[provides]   rte_eth_dev_info**: ``hash_key_size``.
>>>>>> -* **[related]    API**: ``rte_eth_dev_rss_hash_update()``,
>>>>>> +* **[related]    API**: ``rte_eth_dev_configure``,
>>>>>> ``rte_eth_dev_rss_hash_update()``,
>>>>>> +  ``rte_eth_dev_rss_hash_conf_get()``.
>>>>>> +
>>>>> ack
>>>>>
>>>>> There is an inconsistency in the documentation but I think it is
>>>>> good to
>>>>> use '()' when documenting API, like: 'rte_eth_dev_configure()'
>>>> +1 will fix it.
>>>>>> +
>>>>>> +.. _nic_features_rss_hash_algo_update:
>>>>>> +
>>>>>> +RSS hash algorithm update
>>>>>> +-------------------------
>>>>>> +
>>>>>> +Supports configuration of Receive Side Scaling (RSS) hash algorithm.
>>>>>> Updating
>>>>>> +RSS hash algorithm.
>>>>>> +
>>>>>> +* **[implements] eth_dev_ops**: ``dev_configure``,
>>>>>> ``rss_hash_update``, ``rss_hash_conf_get``.
>>>>>> +* **[uses]     user config**: ``rss_conf.algorithm``
>>>>>> +* **[provides]   rte_eth_dev_info**: ``rss_algo_capa``.
>>>>>> +* **[related]    API**: ``rte_eth_dev_configure``,
>>>>>> ``rte_eth_dev_rss_hash_update()``,
>>>>>>       ``rte_eth_dev_rss_hash_conf_get()``.
>>>>>>       
>>>>> This document describes features listed in the 'default.ini', so we
>>>>> shouldn't have above.
>>>>>
>>>>> And I don't think RSS hash algorithm update is a big enough feature to
>>>>> list in the feature list, perhaps it can be embedded in the RSS support
>>>>> block, what do you think?
>>>> Yes it is not a bit feature.
>>>> so put it to RSS hash, right?
>>>>
>>> Yes please.
>>>
>>> .
> .