Author: tuexen Date: Thu May 9 07:11:08 2019 New Revision: 347381 URL: https://svnweb.freebsd.org/changeset/base/347381
Log: 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 Modified: head/sys/netinet/cc/cc_cubic.c head/sys/netinet/cc/cc_htcp.c head/sys/netinet/cc/cc_newreno.c Modified: head/sys/netinet/cc/cc_cubic.c ============================================================================== --- head/sys/netinet/cc/cc_cubic.c Thu May 9 04:16:31 2019 (r347380) +++ head/sys/netinet/cc/cc_cubic.c Thu May 9 07:11:08 2019 (r347381) @@ -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 * Modified: head/sys/netinet/cc/cc_htcp.c ============================================================================== --- head/sys/netinet/cc/cc_htcp.c Thu May 9 04:16:31 2019 (r347380) +++ head/sys/netinet/cc/cc_htcp.c Thu May 9 07:11:08 2019 (r347381) @@ -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)) Modified: head/sys/netinet/cc/cc_newreno.c ============================================================================== --- head/sys/netinet/cc/cc_newreno.c Thu May 9 04:16:31 2019 (r347380) +++ head/sys/netinet/cc/cc_newreno.c Thu May 9 07:11:08 2019 (r347381) @@ -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); } _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
