Re: [PATCH v5 1/2] ethdev: introduce the Tx map API for aggregated ports

[Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>]

On 2/16/23 20:58, Ferruh Yigit wrote:
> On 2/14/2023 3:48 PM, Jiawei Wang wrote:
>> When multiple ports are aggregated into a single DPDK port,
>> (example: Linux bonding, DPDK bonding, failsafe, etc.),
>> we want to know which port use for Tx via a queue.
>>
>> This patch introduces the new ethdev API
>> rte_eth_dev_map_aggr_tx_affinity(), it's used to map a Tx queue
>> with an aggregated port of the DPDK port (specified with port_id),
>> The affinity is the number of the aggregated port.
>> Value 0 means no affinity and traffic could be routed to any
>> aggregated port, this is the default current behavior.
>>
>> The maximum number of affinity is given by rte_eth_dev_count_aggr_ports().
>>
>> Add the trace point for ethdev rte_eth_dev_count_aggr_ports()
>> and rte_eth_dev_map_aggr_tx_affinity() functions.
>>
>> Add the testpmd command line:
>> testpmd> port config (port_id) txq (queue_id) affinity (value)
>>
>> For example, there're two physical ports connected to
>> a single DPDK port (port id 0), and affinity 1 stood for
>> the first physical port and affinity 2 stood for the second
>> physical port.
>> Use the below commands to config tx phy affinity for per Tx Queue:
>>          port config 0 txq 0 affinity 1
>>          port config 0 txq 1 affinity 1
>>          port config 0 txq 2 affinity 2
>>          port config 0 txq 3 affinity 2
>>
>> These commands config the Tx Queue index 0 and Tx Queue index 1 with
>> phy affinity 1, uses Tx Queue 0 or Tx Queue 1 send packets,
>> these packets will be sent from the first physical port, and similar
>> with the second physical port if sending packets with Tx Queue 2
>> or Tx Queue 3.
>>
>> Signed-off-by: Jiawei Wang <jiaweiw@nvidia.com>
> 
> <...>
> 
>> diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
>> index dc0a4eb12c..1d5b3a16b2 100644
>> --- a/lib/ethdev/rte_ethdev.c
>> +++ b/lib/ethdev/rte_ethdev.c
>> @@ -6915,6 +6915,55 @@ rte_eth_buffer_split_get_supported_hdr_ptypes(uint16_t port_id, uint32_t *ptypes
>>   	return j;
>>   }
>>   
>> +int rte_eth_dev_count_aggr_ports(uint16_t port_id)
>> +{
>> +	struct rte_eth_dev *dev;
>> +	int ret;
>> +
>> +	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
>> +	dev = &rte_eth_devices[port_id];
>> +
>> +	if (*dev->dev_ops->count_aggr_ports == NULL)
>> +		return -ENOTSUP;
> 
> What do you think to return a default value when dev_ops is not defined,
> assuming device is not a bounded device.
> Not sure which one is better for application, return a default value or
> error.

I think 0 is better here. It simply means that
rte_eth_dev_map_aggr_tx_affinity() cannot be used as
well as corresponding flow API item.
It will be true even for bonding as long as corresponding
API is not supported.

>> +	ret = eth_err(port_id, (*dev->dev_ops->count_aggr_ports)(port_id));
>> +
>> +	rte_eth_trace_count_aggr_ports(port_id, ret);
>> +
>> +	return ret;
>> +}
>> +
>> +int rte_eth_dev_map_aggr_tx_affinity(uint16_t port_id, uint16_t tx_queue_id,
>> +				     uint8_t affinity)
>> +{
>> +	struct rte_eth_dev *dev;
>> +	int ret;
>> +
>> +	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
>> +	dev = &rte_eth_devices[port_id];
>> +
>> +	if (tx_queue_id >= dev->data->nb_tx_queues) {
>> +		RTE_ETHDEV_LOG(ERR, "Invalid Tx queue_id=%u\n", tx_queue_id);
>> +		return -EINVAL;
>> +	}
>> +
> 
> Although documentation says this API should be called before configure,

Documentation says "after". Anyway, it is better to check vs
dev_configured.

> if user misses it I guess above can crash, is there a way to add runtime
> check, like checking 'dev->data->dev_configured'?
> 
> 
>> +	if (*dev->dev_ops->map_aggr_tx_affinity == NULL)
>> +		return -ENOTSUP;
>> +
>> +	if (dev->data->dev_started) {
>> +		RTE_ETHDEV_LOG(ERR,
>> +			"Port %u must be stopped to allow configuration\n",
>> +			port_id);
>> +		return -EBUSY;
>> +	}
>> +
>> +	ret = eth_err(port_id, (*dev->dev_ops->map_aggr_tx_affinity)(port_id,
>> +				tx_queue_id, affinity));
>> +
> 
> Should API check if port_id is a bonding port before it continue with
> mapping?

Since it is a control path I think it is a good idea to
call rte_eth_dev_count_aggr_ports() and chck affinity value.