Re: [PATCH v4] doc: document NIC features

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 7/8/2017 10:47 AM, Andrew Rybchenko wrote:
> On 07/07/2017 08:21 PM, Ferruh Yigit wrote:
>> Document NIC features, add more information about them and add more
>> implementation related support.
>>
>> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
>> Signed-off-by: John McNamara <john.mcnamara@intel.com>
> 
> Reviewed-by: Andrew Rybchenko <arybchenko@solarflare.com>
> 
> Few minor questions/notes below.
> 
>> ---
>> Cc: Olivier Matz <olivier.matz@6wind.com>
>>
>> v4:
>> * Apply review comments from Andrew Rybchenko
>> * Add tags to the information, to clarify in, out, related data.
>>
>> v3:
>> * received updates from John, Thanks!
>>
>> v2:
>> * Add more details, mbuf and API fields
>> * Formatting added
>>
>> TODO:
>> - Not all features all fully documented, need help from community
>>
>> - Instead of having a new file, it would be nice to auto generate this
>> file from defaults.ini, and perhaps add extra information as comment to
>> that file.
>>
>> - Some features are implementing eth_dev_ops and some are updates in
>> Rx/Tx path. These features can be grouped together.
>>
>> - A link from overview file per feature would be nice.
>> ---
>>   doc/guides/nics/overview.rst          |   4 +
>>   doc/guides/nics/overview_features.rst | 858 ++++++++++++++++++++++++++++++++++
>>   2 files changed, 862 insertions(+)
>>   create mode 100644 doc/guides/nics/overview_features.rst
> 
> <...>
> 
>> +.. _nic_features_rss_hash:
>> +
>> +RSS hash
>> +--------
>> +
>> +Supports RSS hashing on RX.
>> +
>> +* **[uses]     user config**: ``dev_conf.rxmode.mq_mode`` = ``ETH_MQ_RX_RSS_FLAG``.
>> +* **[provides] mbuf**: ``mbuf.ol_flags:PKT_RX_RSS_H()ASH``, ``mbuf.rss``.
> 
> Is it indented that dev_info.flow_type_rss_offloads not mentioned here?

I will add it.

> 
> <...>
> 
>> +
>> +.. _nic_features_inner_l3_checksum:
>> +
>> +Inner L3 checksum
>> +-----------------
>> +
>> +Supports inner packet L3 checksum.
>> +
>> +
>> +.. _nic_features_inner_l4_checksum:
>> +
>> +Inner L4 checksum
>> +-----------------
>> +
>> +Supports inner packet L4 checksum.
>> +
> 
> As I understand outer checksum (PKT_RX_EIP_CKSUM_BAD for Rx) and 
> IPv4/IPv6 flags and
> offload capabilities should be mentioned here. If ourter flags are set, 
> it means that usual checksum
> flags corresponds to inner packet.

I am not sure about these two, that is why I tend to left empty for now,
will update later.

> 
> <...>
> 
>> +
>> +.. _nic_features_rx_descriptor_status:
>> +
>> +Rx descriptor status
>> +--------------------
>> +
>> +Supports check the status of a Rx descriptor. When ``rx_descriptor_status`` is
>> +used, status can be "Available", "Done" or "Unavailable". When
>> +``rx_descriptor_done`` is used, status can be "DD bit is set" or "DD bit is
>> +not set".
>> +
>> +* **[implements] eth_dev_ops**: ``rx_descriptor_status``.
>> +* **[related]    API**: ``rte_eth_rx_descriptor_status()``.
>> +* **[implements] eth_dev_ops**: ``rx_descriptor_done``.
>> +* **[related]    API**: ``rte_eth_rx_descriptor_done()``.
> 
> I'm not sure if _done API should be mentioned here. If yes, may be 
> status of the _done
> API should be highlighted (as far as I remember it was ideas to remove it).

Both looks like valid APIs right now, there is no deprecation note
(__rte_deprecated) on _done API.

Description of feature briefly mentions status values.

> 
> <...>
> 
>> +
>> +.. _nic_features_bsd_nic_uio:
>> +
>> +BSD nic_uio
>> +-----------
>> +
>> +BSD ``nic_uio`` module supported.
>> +
>> +
>> +.. _nic_features_linux_uio:
>> +
>> +Linux UIO
>> +---------
>> +
>> +Works with ``igb_uio`` kernel module.
>> +
>> +
>> +.. _nic_features_linux_vfio:
>> +
>> +Linux VFIO
>> +----------
>> +
>> +Works with ``vfio-pci`` kernel module.
> 
> Should we mention that PMD provides RTE_PMD_REGISTER_KMOD_DEP with 
> corresponding kernel module listed.

Agreed, good to mention about it.

I will send a new version.

> 
> <...>
>