Author: hiren Date: Tue Nov 1 21:08:37 2016 New Revision: 308180 URL: https://svnweb.freebsd.org/changeset/base/308180
Log: Set slow start threshold more accurately on loss to be flightsize/2 instead of cwnd/2 as recommended by RFC5681. (spotted by mmacy at nextbsd dot org) Restore pre-r307901 behavior of aligning ssthresh/cwnd on mss boundary. (spotted by slawa at zxy dot spb dot ru) Tested by: dim, Slawa <slawa at zxy dot spb dot ru> MFC after: 1 month X-MFC with: r307901 Sponsored by: Limelight Networks Differential Revision: https://reviews.freebsd.org/D8349 Modified: head/sys/netinet/cc/cc_cdg.c head/sys/netinet/cc/cc_chd.c head/sys/netinet/cc/cc_dctcp.c head/sys/netinet/cc/cc_htcp.c head/sys/netinet/cc/cc_newreno.c head/sys/netinet/tcp_input.c Modified: head/sys/netinet/cc/cc_cdg.c ============================================================================== --- head/sys/netinet/cc/cc_cdg.c Tue Nov 1 19:18:54 2016 (r308179) +++ head/sys/netinet/cc/cc_cdg.c Tue Nov 1 21:08:37 2016 (r308180) @@ -474,7 +474,9 @@ cdg_cong_signal(struct cc_var *ccv, uint ENTER_RECOVERY(CCV(ccv, t_flags)); break; case CC_RTO: - CCV(ccv, snd_ssthresh) = max(2*mss, cwin/2); + CCV(ccv, snd_ssthresh) = + max((CCV(ccv, snd_max) - CCV(ccv, snd_una)) / 2 / mss, 2) + * mss; CCV(ccv, snd_cwnd) = mss; break; default: Modified: head/sys/netinet/cc/cc_chd.c ============================================================================== --- head/sys/netinet/cc/cc_chd.c Tue Nov 1 19:18:54 2016 (r308179) +++ head/sys/netinet/cc/cc_chd.c Tue Nov 1 21:08:37 2016 (r308180) @@ -330,13 +330,11 @@ chd_cong_signal(struct cc_var *ccv, uint struct ertt *e_t; struct chd *chd_data; int qdly; - uint32_t cwin; u_int mss; e_t = khelp_get_osd(CCV(ccv, osd), ertt_id); chd_data = ccv->cc_data; qdly = imax(e_t->rtt, chd_data->maxrtt_in_rtt) - e_t->minrtt; - cwin = CCV(ccv, snd_cwnd); mss = CCV(ccv, t_maxseg); switch(signal_type) { @@ -378,7 +376,9 @@ chd_cong_signal(struct cc_var *ccv, uint ENTER_FASTRECOVERY(CCV(ccv, t_flags)); break; case CC_RTO: - CCV(ccv, snd_ssthresh) = max(2*mss, cwin/2); + CCV(ccv, snd_ssthresh) = + max((CCV(ccv, snd_max) - CCV(ccv, snd_una)) / 2 / mss, 2) + * mss; CCV(ccv, snd_cwnd) = mss; break; Modified: head/sys/netinet/cc/cc_dctcp.c ============================================================================== --- head/sys/netinet/cc/cc_dctcp.c Tue Nov 1 19:18:54 2016 (r308179) +++ head/sys/netinet/cc/cc_dctcp.c Tue Nov 1 21:08:37 2016 (r308180) @@ -230,19 +230,21 @@ static void dctcp_cong_signal(struct cc_var *ccv, uint32_t type) { struct dctcp *dctcp_data; - uint32_t cwin; + uint32_t cwin, ssthresh_on_loss; u_int mss; dctcp_data = ccv->cc_data; cwin = CCV(ccv, snd_cwnd); mss = CCV(ccv, t_maxseg); + ssthresh_on_loss = + max((CCV(ccv, snd_max) - CCV(ccv, snd_una)) / 2 / mss, 2) + * mss; switch (type) { case CC_NDUPACK: if (!IN_FASTRECOVERY(CCV(ccv, t_flags))) { if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) { - CCV(ccv, snd_ssthresh) = mss * - max(cwin / 2 / mss, 2); + CCV(ccv, snd_ssthresh) = ssthresh_on_loss; dctcp_data->num_cong_events++; } else { /* cwnd has already updated as congestion @@ -250,8 +252,7 @@ dctcp_cong_signal(struct cc_var *ccv, ui * snd_cwnd_prev and recalculate snd_ssthresh */ cwin = CCV(ccv, snd_cwnd_prev); - CCV(ccv, snd_ssthresh) = - max(cwin / 2 / mss, 2) * mss; + CCV(ccv, snd_ssthresh) = ssthresh_on_loss; } ENTER_RECOVERY(CCV(ccv, t_flags)); } @@ -265,8 +266,7 @@ dctcp_cong_signal(struct cc_var *ccv, ui if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) { if (V_dctcp_slowstart && dctcp_data->num_cong_events++ == 0) { - CCV(ccv, snd_ssthresh) = - mss * max(cwin / 2 / mss, 2); + CCV(ccv, snd_ssthresh) = ssthresh_on_loss; dctcp_data->alpha = MAX_ALPHA_VALUE; dctcp_data->bytes_ecn = 0; dctcp_data->bytes_total = 0; @@ -285,7 +285,7 @@ dctcp_cong_signal(struct cc_var *ccv, ui dctcp_update_alpha(ccv); dctcp_data->save_sndnxt += CCV(ccv, t_maxseg); dctcp_data->num_cong_events++; - CCV(ccv, snd_ssthresh) = max(2 * mss, cwin / 2); + CCV(ccv, snd_ssthresh) = ssthresh_on_loss; CCV(ccv, snd_cwnd) = mss; } break; Modified: head/sys/netinet/cc/cc_htcp.c ============================================================================== --- head/sys/netinet/cc/cc_htcp.c Tue Nov 1 19:18:54 2016 (r308179) +++ head/sys/netinet/cc/cc_htcp.c Tue Nov 1 21:08:37 2016 (r308180) @@ -325,7 +325,9 @@ htcp_cong_signal(struct cc_var *ccv, uin */ if (CCV(ccv, t_rxtshift) >= 2) htcp_data->t_last_cong = ticks; - CCV(ccv, snd_ssthresh) = max(2 * mss, cwin / 2); + CCV(ccv, snd_ssthresh) = + max((CCV(ccv, snd_max) - CCV(ccv, snd_una)) / 2 / mss, 2) + * mss; CCV(ccv, snd_cwnd) = mss; break; } @@ -518,6 +520,10 @@ htcp_ssthresh_update(struct cc_var *ccv) CCV(ccv, snd_ssthresh) = ((u_long)CCV(ccv, snd_cwnd) * htcp_data->beta) >> HTCP_SHIFT; } + + /* Align ssthresh to MSS boundary */ + CCV(ccv, snd_ssthresh) = (CCV(ccv, snd_ssthresh) / CCV(ccv, t_maxseg)) + * CCV(ccv, t_maxseg); } Modified: head/sys/netinet/cc/cc_newreno.c ============================================================================== --- head/sys/netinet/cc/cc_newreno.c Tue Nov 1 19:18:54 2016 (r308179) +++ head/sys/netinet/cc/cc_newreno.c Tue Nov 1 21:08:37 2016 (r308180) @@ -182,23 +182,26 @@ newreno_after_idle(struct cc_var *ccv) static void newreno_cong_signal(struct cc_var *ccv, uint32_t type) { - uint32_t cwin; + uint32_t cwin, ssthresh_on_loss; u_int mss; cwin = CCV(ccv, snd_cwnd); mss = CCV(ccv, t_maxseg); + ssthresh_on_loss = + max((CCV(ccv, snd_max) - CCV(ccv, snd_una)) / 2 / mss, 2) + * mss; /* Catch algos which mistakenly leak private signal types. */ KASSERT((type & CC_SIGPRIVMASK) == 0, ("%s: congestion signal type 0x%08x is private\n", __func__, type)); - cwin = max(2*mss, cwin/2); + cwin = max(cwin / 2 / mss, 2) * mss; switch (type) { case CC_NDUPACK: if (!IN_FASTRECOVERY(CCV(ccv, t_flags))) { if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) { - CCV(ccv, snd_ssthresh) = cwin; + CCV(ccv, snd_ssthresh) = ssthresh_on_loss; CCV(ccv, snd_cwnd) = cwin; } ENTER_RECOVERY(CCV(ccv, t_flags)); @@ -206,13 +209,13 @@ newreno_cong_signal(struct cc_var *ccv, break; case CC_ECN: if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) { - CCV(ccv, snd_ssthresh) = cwin; + CCV(ccv, snd_ssthresh) = ssthresh_on_loss; CCV(ccv, snd_cwnd) = cwin; ENTER_CONGRECOVERY(CCV(ccv, t_flags)); } break; case CC_RTO: - CCV(ccv, snd_ssthresh) = cwin; + CCV(ccv, snd_ssthresh) = ssthresh_on_loss; CCV(ccv, snd_cwnd) = mss; break; } Modified: head/sys/netinet/tcp_input.c ============================================================================== --- head/sys/netinet/tcp_input.c Tue Nov 1 19:18:54 2016 (r308179) +++ head/sys/netinet/tcp_input.c Tue Nov 1 21:08:37 2016 (r308180) @@ -444,7 +444,8 @@ cc_cong_signal(struct tcpcb *tp, struct * ssthresh = max (FlightSize / 2, 2*SMSS) eq (4) */ tp->snd_ssthresh = - max((tp->snd_max - tp->snd_una) / 2, 2 * maxseg); + max((tp->snd_max - tp->snd_una) / 2 / maxseg, 2) + * maxseg; tp->snd_cwnd = maxseg; } break; _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
