Re: multiple rx/tx rings and interrupt delivery on newer nics

[Sepherosa Ziehau <sepherosa%gmail.com@localhost>]

On Tue, Mar 17, 2009 at 7:48 PM, Darren Reed <darrenr%netbsd.org@localhost> 
wrote:
> Thor Lancelot Simon wrote:
>> On Fri, Mar 13, 2009 at 05:47:38PM +0100, Manuel Bouyer wrote:
>>> We'd need a generic way to add priority tags to packets, and then
>>> use it in NIC drivers.
>>
>> But most modern NICs can use multiple receive rings based on much
>> richer (and more useful) criteria than just priority.  And, generally
>> speaking, you never want anything in the system to touch all packets --
>> you want them segregated to a receive ring based on, for example,
>> source and destination address and port, and you never want anything
>> that's not on CPU N to touch receive ring N.
>
> Right.
>
> Hardware classification on server NICs now supports using the
> complete 5-tuple (srcip, dstip, protocol, srcport, dstport) as

Only TCP uses {faddr,laddr,fport,lport} tuple, rest just use
{faddr,laddr}.  AFAIK, many NICs (e.g. intel's 8257x) could not
differentiate IP fragments and non-UDP/non-TCP non-fragmented packets.

Best Regards,
sephe

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