[PATCH v12 04/12] net/tap: validate and setup parameters for BPF RSS

[Ferruh Yigit]

On 5/21/2024 3:01 AM, Stephen Hemminger wrote:
> On Mon, 20 May 2024 18:47:08 +0100
> Ferruh Yigit <ferruh.yigit at amd.com> wrote:
> 
>>> +
>>>  
>>
>> Why 'rte_convert_rss_key()' is required? Is this making an assumption on
>> the CPU architecture?
> 
> 
> What is happening here is that the key passed in is in cpu native
> order, but the SW RSS algorithm needs it to be in big-endian to
> work with IP protocols that are big-endian.
> 
> In rte_thash the code to convert key is: rte_convert_rss_key()
> and the code use the converted key is rte_softrss_be().
> 
> The BPF code doesn't (and cant easily because of license/validator) use the same
> exact routine but it is equivalent to rte_softrss_be and uses pre-converted
> key for performance.
>

got it, thanks for clarification. If there will be a new version, I
think it helps others to add a comment before the call, up to you.