[ntp:questions] Sub-millisecond NTP synchronization for local network

Rick Jones rick.jones2 at hp.com
Tue Dec 9 01:27:16 UTC 2008


Ryan Malayter <malayter at gmail.com> wrote:
> On Mon, Dec 8, 2008 at 11:57 AM, Rick Jones <rick.jones2 at hp.com> wrote:
> > "All" the 10G NICs and I suspect a decent number of the 1G NICs
> > support TSO or TCP/Transport Segmentation Offload.  For the sender at
> > least that can be considered a "poor man's jumbo frame."  Many (most?)
> > of the curent 10G NICs also support LRO or Large Receive Offload.

> I don't think you'll ever see baseline support for such features on
> Linux. The kernel guys fundamentally disagree with TCP offload:
> http://www.linuxfoundation.org/en/Net:TOE

I believe you are confusing TSO and LRO, which are stateless offloads
(TCP connection state) with TOE (TCP Offload Engine) which is a
statefull offload - TCP connection state kept in the card rather than
the host stack.  It is indeed true there is a considerable and likely
to continue immune response in "netdev" to TOE, but they are quite
pleased with stateless offloads like TSO and LRO.

rick jones
-- 
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