Re: [dpdk-dev] [PATCH] ethdev: check for Rx RSS distribution and RSS hash

[oulijun <oulijun@huawei.com>]

在 2020/4/27 20:49, Andrew Rybchenko 写道:
> On 4/27/20 3:34 PM, Lijun Ou wrote:
>> When rte api checks the Rx RSS distribution is enable but the RSS
>> hash is disabled, it will return an error.
>>
>> Signed-off-by: Lijun Ou <oulijun@huawei.com>
>> ---
>>   lib/librte_ethdev/rte_ethdev.c | 11 +++++++++++
>>   1 file changed, 11 insertions(+)
>>
>> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
>> index 0854ef8..07734c4 100644
>> --- a/lib/librte_ethdev/rte_ethdev.c
>> +++ b/lib/librte_ethdev/rte_ethdev.c
>> @@ -1411,6 +1411,17 @@ rte_eth_dev_configure(uint16_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q,
>>   		goto rollback;
>>   	}
>>   
>> +	/* Check if Rx RSS distribution is enable but RSS hash is disabled. */
>> +	if (((dev_conf->rxmode.mq_mode & ETH_MQ_RX_RSS_FLAG) != 0) &&
>> +	    !(dev_conf->rxmode.offloads & DEV_RX_OFFLOAD_RSS_HASH)) {
>> +		RTE_ETHDEV_LOG(ERR,
>> +			"Ethdev port_id=%u config valid Rx mq_mode with RSS but %s offload is no-requested\n",
>> +			port_id,
>> +			rte_eth_dev_rx_offload_name(DEV_RX_OFFLOAD_RSS_HASH));
>> +		ret = -EINVAL;
>> +		goto rollback;
>> +	}
>> +
>>   	/*
>>   	 * Setup new number of RX/TX queues and reconfigure device.
>>   	 */
> 
> NACK. It is perfectly fine to do distribution, but do not need RSS hash
> information.
>   - ETH_MQ_RX_RSS_FLAG controls RSS hash calculation and distribution
>   - DEV_RX_OFFLOAD_RSS_HASH controls delivery of the hash value
>     itself from HW to SW
> 
Thanks for your detail explanation. I still have a question, what is the 
use of setting DEV_RX_OFFLOAD_HASH, what is the difference between user 
configuration DEV_RX_OFFLOAD_HASH and no configuration?

> .
>