Prevent cwnd to collapse down to 1 MSS after exiting recovery.

This is descrined in RFC 6582, which updates RFC 3782.

Submitted by:		Richard Scheffenegger
Reviewed by:		lstewart@
MFC after:		1 week
Differential Revision:	https://reviews.freebsd.org/D17614
This commit is contained in:
Michael Tuexen 2019-05-09 07:11:08 +00:00
parent 6ca363eb7b
commit 5cc11a89db
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=347381
3 changed files with 18 additions and 3 deletions

View File

@ -324,7 +324,12 @@ cubic_post_recovery(struct cc_var *ccv)
pipe = CCV(ccv, snd_max) - ccv->curack;
if (pipe < CCV(ccv, snd_ssthresh))
CCV(ccv, snd_cwnd) = pipe + CCV(ccv, t_maxseg);
/*
* Ensure that cwnd does not collapse to 1 MSS under
* adverse conditions. Implements RFC6582
*/
CCV(ccv, snd_cwnd) = max(pipe, CCV(ccv, t_maxseg)) +
CCV(ccv, t_maxseg);
else
/* Update cwnd based on beta and adjusted max_cwnd. */
CCV(ccv, snd_cwnd) = max(1, ((CUBIC_BETA *

View File

@ -366,7 +366,12 @@ htcp_post_recovery(struct cc_var *ccv)
pipe = CCV(ccv, snd_max) - ccv->curack;
if (pipe < CCV(ccv, snd_ssthresh))
CCV(ccv, snd_cwnd) = pipe + CCV(ccv, t_maxseg);
/*
* Ensure that cwnd down not collape to 1 MSS under
* adverse conditions. Implements RFC6582
*/
CCV(ccv, snd_cwnd) = max(pipe, CCV(ccv, t_maxseg)) +
CCV(ccv, t_maxseg);
else
CCV(ccv, snd_cwnd) = max(1, ((htcp_data->beta *
htcp_data->prev_cwnd / CCV(ccv, t_maxseg))

View File

@ -295,7 +295,12 @@ newreno_post_recovery(struct cc_var *ccv)
pipe = CCV(ccv, snd_max) - ccv->curack;
if (pipe < CCV(ccv, snd_ssthresh))
CCV(ccv, snd_cwnd) = pipe + CCV(ccv, t_maxseg);
/*
* Ensure that cwnd does not collapse to 1 MSS under
* adverse conditons. Implements RFC6582
*/
CCV(ccv, snd_cwnd) = max(pipe, CCV(ccv, t_maxseg)) +
CCV(ccv, t_maxseg);
else
CCV(ccv, snd_cwnd) = CCV(ccv, snd_ssthresh);
}