Re: Receive Side Coalescing(RSC) and LRO

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From: Hans Petter Selasky <hps_at_selasky.org>
Date: Wed, 09 Feb 2022 12:08:17 UTC

On 2/9/22 10:28, Wei Hu wrote:
> But maybe it is the way to go as FreeBSD lacks system wide support to differentiate hardware and software LRO.

Hi Wei,

Software LRO has been found superior to hardware LRO, especially when 
hundreds of connections are involved. The hardware is simply not able 
keep up.

For few connections, hardware LRO may give some performance benefits, 
but I would rather recommend RoCE/Infiniband for such use-cases, because 
at the high rates involved, even a single packet loss will cause 
terrible performance degradation.

Personally, I don't see a need for hardware LRO.

BTW: kib@ is working on adding more capability bits for ifconfig via nv 
lists. You might be interested in that:

https://reviews.freebsd.org/D32551

--HPS