svn commit: r294327 - in head/sys: dev/cxgb dev/cxgbe dev/e1000 dev/hyperv/netvsc dev/ixgbe dev/mxge netinet sys

[Adrian Chadd]

On 19 January 2016 at 12:24, Hans Petter Selasky <hps at selasky.org> wrote:
> On 01/19/16 21:05, Adrian Chadd wrote:
>>
>> Erm, ok. So I'm confused about the state of how the streams are
>> tracked. So not all mbufs are in a stream, but they're in some single
>> LRO mbuf list?
>>
>
> Hi,
>
> The streams are typically tracked using the hardware generated Toeplitz hash
> value. The mbufs are sorted according to the hash value and the hash type.
> The list of mbufs is scanned, flushing the LRO entries every time we see a
> change in the hash value or hash type. OK?

Sure, but TCP fragments and non-fragments can hash to different
values, so suddenly you get interleaved packets.

You can't rely on the toeplitz hash 100% hashing /all packets in a
stream/ reliably, because it's highly dependent upon the NIC config.

This is why I did all that effort in the RSS code to handle things.

-a