Re: [PATCH v3 1/4] ethdev: introduce ethdev HW desc dump PI

[Dongdong Liu <liudongdong3@huawei.com>]

Hi Andrew

Many thanks for your review.

On 2022/6/2 3:53, Andrew Rybchenko wrote:
> On 6/1/22 10:49, Min Hu (Connor) wrote:
>> Added the ethdev HW Rx desc dump API which provides functions for query
>> HW descriptor from device. HW descriptor info differs in different NICs.
>> The information demonstrates I/O process which is important for debug.
>> As the information is different between NICs, the new API is introduced.
>>
>> Signed-off-by: Min Hu (Connor) <humin29@huawei.com>
>> ---
>>   doc/guides/rel_notes/release_22_07.rst |  7 ++++
>>   lib/ethdev/ethdev_driver.h             | 42 ++++++++++++++++++++++++
>>   lib/ethdev/rte_ethdev.c                | 44 ++++++++++++++++++++++++++
>>   lib/ethdev/rte_ethdev.h                | 44 ++++++++++++++++++++++++++
>>   lib/ethdev/version.map                 |  2 ++
>>   5 files changed, 139 insertions(+)
>>
>> diff --git a/doc/guides/rel_notes/release_22_07.rst
>> b/doc/guides/rel_notes/release_22_07.rst
>> index 8932a1d478..56c675121a 100644
>> --- a/doc/guides/rel_notes/release_22_07.rst
>> +++ b/doc/guides/rel_notes/release_22_07.rst
>> @@ -137,6 +137,13 @@ New Features
>>     * ``RTE_EVENT_QUEUE_ATTR_WEIGHT``
>>     * ``RTE_EVENT_QUEUE_ATTR_AFFINITY``
>>   +* **Added ethdev HW desc dump API, to dump Rx/Tx HW desc info from
>> device.**
>> +
>> +  Added the ethdev HW Rx desc dump API which provides functions for
>> query
>> +  HW descriptor from device. HW descriptor info differs in different
>> NICs.
>> +  The information demonstrates I/O process which is important for debug.
>> +  As the information is different between NICs, the new API is
>> introduced.
>> +
>>     Removed Items
>>   -------------
>> diff --git a/lib/ethdev/ethdev_driver.h b/lib/ethdev/ethdev_driver.h
>> index 69d9dc21d8..9c1726eb2d 100644
>> --- a/lib/ethdev/ethdev_driver.h
>> +++ b/lib/ethdev/ethdev_driver.h
>> @@ -1073,6 +1073,42 @@ typedef int
>> (*eth_ip_reassembly_conf_set_t)(struct rte_eth_dev *dev,
>>    */
>>   typedef int (*eth_dev_priv_dump_t)(struct rte_eth_dev *dev, FILE
>> *file);
>>   +/**
>> + * @internal
>> + * Dump ethdev Rx descriptor info to a file.
>
> ethdev is not required in the description above. It is an ethdev
> operation type.

Will remove it.
>
> Is there any limitations on caller context? Should be it the same
> CPU core (since typically it is the case for per-queue API) which
> polls the queue? The answer must be in the API function description.

"[PATCH v3 4/4] app/procinfo: support descriptor dump" shows how to use
the API. It is used for debug, not a dataplane API,  no special
limitations on caller context.

>
>> + *
>> + * @param file
>> + *   A pointer to a file for output.
>> + * @param dev
>> + *   Port (ethdev) handle.
>> + * @param queue_id
>> + *   The selected queue.
>> + * @param desc_id
>> + *   The selected descriptor.
>
> Is it an ID in the ring regardless of the current position or
> is it offset relative to current position in the ring?
> It should be clarified in any case.
> I'd say that it should be an offset to be consistent with
> descriptor status API.

It is an ID in the ring regardless of the current position.
>
> It would be useful to be able to dump many descriptor at once.
This can be done by the appliacation.
>
>> + * @return
>> + *   Negative errno value on error, zero on success.
>> + */
>> +typedef int (*eth_rx_hw_desc_dump_t)(FILE *file, const struct
>> rte_eth_dev *dev,
>> +                     uint16_t queue_id, uint16_t desc_id);
>> +
>> +/**
>> + * @internal
>> + * Dump ethdev Tx descriptor info to a file.
>> + *
>> + * @param file
>> + *   A pointer to a file for output.
>> + * @param dev
>> + *   Port (ethdev) handle.
>> + * @param queue_id
>> + *   The selected queue.
>> + * @param desc_id
>> + *   The selected descriptor.
>> + * @return
>> + *   Negative errno value on error, zero on success.
>> + */
>> +typedef int (*eth_tx_hw_desc_dump_t)(FILE *file, const struct
>> rte_eth_dev *dev,
>> +                     uint16_t queue_id, uint16_t desc_id);
>> +
>>   /**
>>    * @internal A structure containing the functions exported by an
>> Ethernet driver.
>>    */
>> @@ -1283,6 +1319,12 @@ struct eth_dev_ops {
>>         /** Dump private info from device */
>>       eth_dev_priv_dump_t eth_dev_priv_dump;
>> +
>> +    /** Dump ethdev Rx descriptor info */\\
>
> It is an ethdev operations. So, 'ethdev' is not necessary in the
> description.
Will fix.
>
>> +    eth_rx_hw_desc_dump_t eth_rx_hw_desc_dump;
>> +
>> +    /** Dump ethdev Tx descriptor info */
>> +    eth_tx_hw_desc_dump_t eth_tx_hw_desc_dump;
>>   };
>>     /**
>> diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
>> index 46c088dc88..bbd8439fa0 100644
>> --- a/lib/ethdev/rte_ethdev.c
>> +++ b/lib/ethdev/rte_ethdev.c
>> @@ -5876,6 +5876,50 @@ rte_eth_dev_priv_dump(uint16_t port_id, FILE
>> *file)
>>       return eth_err(port_id, (*dev->dev_ops->eth_dev_priv_dump)(dev,
>> file));
>>   }
>>   +int
>> +rte_eth_rx_hw_desc_dump(FILE *file, uint16_t port_id, uint16_t queue_id,
>> +            uint16_t desc_id)
>> +{
>> +    struct rte_eth_dev *dev;
>> +    int ret;
>> +
>> +    RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
>> +    dev = &rte_eth_devices[port_id];
>
> Shouldn't we check file vs null?
Yes, will do.
>
>> +
>> +    if (queue_id >= dev->data->nb_rx_queues) {
>> +        RTE_ETHDEV_LOG(ERR, "Invalid Rx queue_id=%u\n", queue_id);
>> +        return -EINVAL;
>> +    }
>
> Don't we need a check vs queue size?

This need to be done in pmd as "[PATCH v3 3/4] net/hns3: support Rx/Tx 
bd dump" shows.

Thanks,
Dongdong
>
>> +
>> +    RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->eth_rx_hw_desc_dump,
>> -ENOTSUP);
>> +    ret = (*dev->dev_ops->eth_rx_hw_desc_dump)(file, dev, queue_id,
>> +                           desc_id);
>> +
>> +    return ret;
>> +}
>
> .
>