netdev - Re: [PATCH net-next 3/4] tcp: add SACK compression

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Date:   Thu, 17 May 2018 10:15:16 -0700
From:   Eric Dumazet <edumazet@...gle.com>
To:     Yuchung Cheng <ycheng@...gle.com>
Cc:     Neal Cardwell <ncardwell@...gle.com>,
        Eric Dumazet <eric.dumazet@...il.com>,
        David Miller <davem@...emloft.net>,
        netdev <netdev@...r.kernel.org>,
        Toke Høiland-Jørgensen <toke@...e.dk>,
        Soheil Hassas Yeganeh <soheil@...gle.com>,
        Christoph Paasch <cpaasch@...le.com>
Subject: Re: [PATCH net-next 3/4] tcp: add SACK compression

On Thu, May 17, 2018 at 9:59 AM Yuchung Cheng <ycheng@...gle.com> wrote:
> >
> > Thanks for implementing this! Overall this patch seems nice to me.
> >
> > Acked-by: Neal Cardwell <ncardwell@...gle.com>
> >
> > BTW, I guess we should spread the word to maintainers of other major TCP
> > stacks that they need to be prepared for what may be a much higher
degree
> > of compression/aggregation in the SACK stream. Linux stacks going back
many
> > years should be fine with this, but I'm not sure about the other major
OSes
> > (they may only allow sending one MSS per ACK-with-SACKs received).
> Patch looks really good but Neal's comment just reminds me a potential
> legacy issue.

> I recall at least Apple and Windows TCP stacks still need 3+ DUPACKs
> (!= a SACK covering 3+ packets) to trigger fast recovery. Will we have
> an issue there interacting w/ these stacks?


Then we should revert GRO :)

Really it is time for these stacks to catch up, or give up to QUIC :/