Re: [PATCH net-next v2] tcp: Ensure DCTCP reacts to losses

From: Neal Cardwell
Date: Thu Apr 04 2019 - 09:55:39 EST


On Thu, Apr 4, 2019 at 9:48 AM Neal Cardwell <ncardwell@xxxxxxxxxx> wrote:
>
> On Thu, Apr 4, 2019 at 8:24 AM Tilmans, Olivier (Nokia - BE/Antwerp)
> <olivier.tilmans@xxxxxxxxxxxxxxxxxxx> wrote:
> >
> > From: Koen De Schepper <koen.de_schepper@xxxxxxxxxxxxxxxxxxx>
> >
> > RFC8257 Â3.5 explicitly states that "A DCTCP sender MUST react to
> > loss episodes in the same way as conventional TCP".
> ...
> > This patch replace the clamping of alpha by setting ssthresh to
> > half of cwnd for both fast retransmissions and RTOs, at most once
> > per RTT. Consequently, the dctcp_clamp_alpha_on_loss module parameter
> > has been removed.
>
> Acked-by: Neal Cardwell <ncardwell@xxxxxxxxxx>
>
> Thanks!

FWIW, my vote is that this is an important bug fix that is appropriate
for the net branch and -stable releases, rather than net-next.

neal