[dpdk-dev] Questions Questions about hash function enum

[oulijun]

在 2020/6/3 1:13, Ferruh Yigit 写道:
> On 6/1/2020 2:31 AM, oulijun wrote:
>> Hi Ferruh Yigit and others
>>
>>      I am learning data structure defined by dpdk framework and I noticed
>> a data structure definition below:
>>
>> enum rte_eth_hash_function {
>>       RTE_ETH_HASH_FUNCTION_DEFAULT = 0,
>>       RTE_ETH_HASH_FUNCTION_TOEPLITZ, /**< Toeplitz */
>>       RTE_ETH_HASH_FUNCTION_SIMPLE_XOR, /**< Simple XOR */
>>       /**
>>        * Symmetric Toeplitz: src, dst will be replaced by
>>        * xor(src, dst). For the case with src/dst only,
>>        * src or dst address will xor with zero pair.
>>        */
>>       RTE_ETH_HASH_FUNCTION_SYMMETRIC_TOEPLITZ,
>>       RTE_ETH_HASH_FUNCTION_MAX,
>> };
>>
>> I have a little difficulty understanding that for the comment:
>>
>>      /**
>>        * Symmetric Toeplitz: src, dst will be replaced by
>>        * xor(src, dst). For the case with src/dst only,
>>        * src or dst address will xor with zero pair.
>>        */
>>
>> if user configure rss func for symmetric toeplitz, Rss type must be
>> updated at the same time?
>>
>> if user configure rss func for xor, rss type must be empty and the queue
>> number is zero?
>>
>> Must it be restricted like this? If so, what is his benefit?
>>
>> Looking forward to your reply
> 
> cc'ed Qi & Andrew
> 
> As far as I understand that comment is only describing the Symmetric Toeplitz
> behavior. I don't see any rss type or queue number limitation.
> 
Hi Qi & Andrew
    if user configure rss func for symmetric toeplitz, RSS types must be 
updated at the same time?
flow create 0 ingress pattern end actions rss func symmetric_toepilitz 
types tcp end / end

if use the following cmd:
flow create 0 ingress pattern end actions rss func symmetric_toepilitz 
types end / end

it is wrong and the driver will print the error info.
How to understand this limitation?

Thanks
Lijun Ou

> 
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