[dpdk-dev] [PATCH 2/2] net/bonding: support configuring Tx offloading for bonding

[Andrew Rybchenko]

On 6/9/21 12:11 PM, Ananyev, Konstantin wrote:
> 
>>
>>
>> On 2021/6/8 17:49, Andrew Rybchenko wrote:
>>> "for bonding" is redundant in the summary since it is already
>>> "net/bonding"
>>>
>>> On 4/23/21 12:46 PM, Chengchang Tang wrote:
>>>> Currently, the TX offloading of the bonding device will not take effect by
>>>
>>> TX -> Tx
>>>
>>>> using dev_configure. Because the related configuration will not be
>>>> delivered to the slave devices in this way.
>>>
>>> I think it is a major problem that Tx offloads are actually
>>> ignored. It should be a patches with "Fixes:" which addresses
>>> it.
>>>
>>>> The Tx offloading capability of the bonding device is the intersection of
>>>> the capability of all slave devices. Based on this, the following functions
>>>> are added to the bonding driver:
>>>> 1. If a Tx offloading is within the capability of the bonding device (i.e.
>>>> all the slave devices support this Tx offloading), the enabling status of
>>>> the offloading of all slave devices depends on the configuration of the
>>>> bonding device.
>>>>
>>>> 2. For the Tx offloading that is not within the Tx offloading capability
>>>> of the bonding device, the enabling status of the offloading on the slave
>>>> devices is irrelevant to the bonding device configuration. And it depends
>>>> on the original configuration of the slave devices.
>>>>
>>>> Signed-off-by: Chengchang Tang <tangchengchang at huawei.com>
>>>> ---
>>>>  drivers/net/bonding/rte_eth_bond_pmd.c | 13 +++++++++++++
>>>>  1 file changed, 13 insertions(+)
>>>>
>>>> diff --git a/drivers/net/bonding/rte_eth_bond_pmd.c b/drivers/net/bonding/rte_eth_bond_pmd.c
>>>> index 84af348..9922657 100644
>>>> --- a/drivers/net/bonding/rte_eth_bond_pmd.c
>>>> +++ b/drivers/net/bonding/rte_eth_bond_pmd.c
>>>> @@ -1712,6 +1712,8 @@ slave_configure(struct rte_eth_dev *bonded_eth_dev,
>>>>  	struct rte_flow_error flow_error;
>>>>
>>>>  	struct bond_dev_private *internals = bonded_eth_dev->data->dev_private;
>>>> +	uint64_t tx_offload_cap = internals->tx_offload_capa;
>>>> +	uint64_t tx_offload;
>>>>
>>>>  	/* Stop slave */
>>>>  	errval = rte_eth_dev_stop(slave_eth_dev->data->port_id);
>>>> @@ -1759,6 +1761,17 @@ slave_configure(struct rte_eth_dev *bonded_eth_dev,
>>>>  		slave_eth_dev->data->dev_conf.rxmode.offloads &=
>>>>  				~DEV_RX_OFFLOAD_JUMBO_FRAME;
>>>>
>>>> +	while (tx_offload_cap != 0) {
>>>> +		tx_offload = 1ULL << __builtin_ctzll(tx_offload_cap);
>>>> +		if (bonded_eth_dev->data->dev_conf.txmode.offloads & tx_offload)
>>>> +			slave_eth_dev->data->dev_conf.txmode.offloads |=
>>>> +				tx_offload;
>>>> +		else
>>>> +			slave_eth_dev->data->dev_conf.txmode.offloads &=
>>>> +				~tx_offload;
>>>> +		tx_offload_cap &= ~tx_offload;
>>>> +	}
>>>> +
>>>
>>> Frankly speaking I don't understand why it is that complicated.
>>> ethdev rejects of unsupported Tx offloads. So, can't we simply:
>>> slave_eth_dev->data->dev_conf.txmode.offloads =
>>>     bonded_eth_dev->data->dev_conf.txmode.offloads;
>>>
>>
>> Using such a complicated method is to increase the flexibility of the slave devices,
>> allowing the Tx offloading of the slave devices to be incompletely consistent with
>> the bond device. If some offloading can be turned on without bond device awareness,
>> they can be retained in this case.
> 
> 
> Not sure how that can that happen...

+1

@Chengchang could you provide an example how it could happen.

> From my understanding tx_offload for bond device has to be intersection of tx_offloads
> of all slaves, no? Otherwise bond device might be misconfigured.
> Anyway for that code snippet above, wouldn't the same be achived by:
> slave_eth_dev->data->dev_conf.txmode.offloads &= internals->tx_offload_capa & bonded_eth_dev->data->dev_conf.txmode.offloads;
> ?