Author: tuexen Date: Mon Jul 29 09:19:48 2019 New Revision: 350404 URL: https://svnweb.freebsd.org/changeset/base/350404
Log: When performing after_idle() or post_recovery(), don't disable the DCTCP specific methods. Also fallthrough NewReno for non ECN capable TCP connections and improve the integer arithmetic. Obtained from: Richard Scheffenegger MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D20550 Modified: head/sys/netinet/cc/cc_dctcp.c Modified: head/sys/netinet/cc/cc_dctcp.c ============================================================================== --- head/sys/netinet/cc/cc_dctcp.c Mon Jul 29 08:50:35 2019 (r350403) +++ head/sys/netinet/cc/cc_dctcp.c Mon Jul 29 09:19:48 2019 (r350404) @@ -123,7 +123,7 @@ dctcp_ack_received(struct cc_var *ccv, uint16_t type) newreno_cc_algo.ack_received(ccv, type); if (type == CC_DUPACK) - bytes_acked = CCV(ccv, t_maxseg); + bytes_acked = min(ccv->bytes_this_ack, CCV(ccv, t_maxseg)); if (type == CC_ACK) bytes_acked = ccv->bytes_this_ack; @@ -133,6 +133,8 @@ dctcp_ack_received(struct cc_var *ccv, uint16_t type) /* Update total marked bytes. */ if (dctcp_data->ece_curr) { + //XXRMS: For fluid-model DCTCP, update + //cwnd here during for RTT fairness if (!dctcp_data->ece_prev && bytes_acked > CCV(ccv, t_maxseg)) { dctcp_data->bytes_ecn += @@ -166,18 +168,20 @@ dctcp_after_idle(struct cc_var *ccv) { struct dctcp *dctcp_data; - dctcp_data = ccv->cc_data; + if (CCV(ccv, t_flags) & TF_ECN_PERMIT) { + dctcp_data = ccv->cc_data; - /* Initialize internal parameters after idle time */ - dctcp_data->bytes_ecn = 0; - dctcp_data->bytes_total = 0; - dctcp_data->save_sndnxt = CCV(ccv, snd_nxt); - dctcp_data->alpha = V_dctcp_alpha; - dctcp_data->ece_curr = 0; - dctcp_data->ece_prev = 0; - dctcp_data->num_cong_events = 0; + /* Initialize internal parameters after idle time */ + dctcp_data->bytes_ecn = 0; + dctcp_data->bytes_total = 0; + dctcp_data->save_sndnxt = CCV(ccv, snd_nxt); + dctcp_data->alpha = V_dctcp_alpha; + dctcp_data->ece_curr = 0; + dctcp_data->ece_prev = 0; + dctcp_data->num_cong_events = 0; + } - dctcp_cc_algo.after_idle = newreno_cc_algo.after_idle; + newreno_cc_algo.after_idle(ccv); } static void @@ -228,63 +232,66 @@ static void dctcp_cong_signal(struct cc_var *ccv, uint32_t type) { struct dctcp *dctcp_data; - u_int win, mss; + u_int cwin, mss; - dctcp_data = ccv->cc_data; - win = CCV(ccv, snd_cwnd); - mss = CCV(ccv, t_maxseg); + if (CCV(ccv, t_flags) & TF_ECN_PERMIT) { + dctcp_data = ccv->cc_data; + cwin = CCV(ccv, snd_cwnd); + mss = CCV(ccv, t_maxseg); - switch (type) { - case CC_NDUPACK: - if (!IN_FASTRECOVERY(CCV(ccv, t_flags))) { + switch (type) { + case CC_NDUPACK: + if (!IN_FASTRECOVERY(CCV(ccv, t_flags))) { + if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) { + CCV(ccv, snd_ssthresh) = + max(cwin / 2, 2 * mss); + dctcp_data->num_cong_events++; + } else { + /* cwnd has already updated as congestion + * recovery. Reverse cwnd value using + * snd_cwnd_prev and recalculate snd_ssthresh + */ + cwin = CCV(ccv, snd_cwnd_prev); + CCV(ccv, snd_ssthresh) = + max(cwin / 2, 2 * mss); + } + ENTER_RECOVERY(CCV(ccv, t_flags)); + } + break; + case CC_ECN: + /* + * Save current snd_cwnd when the host encounters both + * congestion recovery and fast recovery. + */ + CCV(ccv, snd_cwnd_prev) = cwin; if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) { - CCV(ccv, snd_ssthresh) = mss * - max(win / 2 / mss, 2); - dctcp_data->num_cong_events++; - } else { - /* cwnd has already updated as congestion - * recovery. Reverse cwnd value using - * snd_cwnd_prev and recalculate snd_ssthresh - */ - win = CCV(ccv, snd_cwnd_prev); - CCV(ccv, snd_ssthresh) = - max(win / 2 / mss, 2) * mss; + if (V_dctcp_slowstart && + dctcp_data->num_cong_events++ == 0) { + CCV(ccv, snd_ssthresh) = + max(cwin / 2, 2 * mss); + dctcp_data->alpha = MAX_ALPHA_VALUE; + dctcp_data->bytes_ecn = 0; + dctcp_data->bytes_total = 0; + dctcp_data->save_sndnxt = CCV(ccv, snd_nxt); + } else + CCV(ccv, snd_ssthresh) = + max((cwin - (((uint64_t)cwin * + dctcp_data->alpha) >> (DCTCP_SHIFT+1))), + 2 * mss); + CCV(ccv, snd_cwnd) = CCV(ccv, snd_ssthresh); + ENTER_CONGRECOVERY(CCV(ccv, t_flags)); } - ENTER_RECOVERY(CCV(ccv, t_flags)); - } - break; - case CC_ECN: - /* - * Save current snd_cwnd when the host encounters both - * congestion recovery and fast recovery. - */ - CCV(ccv, snd_cwnd_prev) = win; - if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) { - if (V_dctcp_slowstart && - dctcp_data->num_cong_events++ == 0) { - CCV(ccv, snd_ssthresh) = - mss * max(win / 2 / mss, 2); - dctcp_data->alpha = MAX_ALPHA_VALUE; - dctcp_data->bytes_ecn = 0; - dctcp_data->bytes_total = 0; - dctcp_data->save_sndnxt = CCV(ccv, snd_nxt); - } else - CCV(ccv, snd_ssthresh) = max((win - ((win * - dctcp_data->alpha) >> 11)) / mss, 2) * mss; - CCV(ccv, snd_cwnd) = CCV(ccv, snd_ssthresh); - ENTER_CONGRECOVERY(CCV(ccv, t_flags)); - } - dctcp_data->ece_curr = 1; - break; - case CC_RTO: - if (CCV(ccv, t_flags) & TF_ECN_PERMIT) { + dctcp_data->ece_curr = 1; + break; + case CC_RTO: CCV(ccv, t_flags) |= TF_ECN_SND_CWR; dctcp_update_alpha(ccv); dctcp_data->save_sndnxt += CCV(ccv, t_maxseg); dctcp_data->num_cong_events++; + break; } - break; - } + } else + newreno_cc_algo.cong_signal(ccv, type); } static void @@ -304,7 +311,7 @@ dctcp_conn_init(struct cc_var *ccv) static void dctcp_post_recovery(struct cc_var *ccv) { - dctcp_cc_algo.post_recovery = newreno_cc_algo.post_recovery; + newreno_cc_algo.post_recovery(ccv); if (CCV(ccv, t_flags) & TF_ECN_PERMIT) dctcp_update_alpha(ccv); @@ -330,8 +337,8 @@ dctcp_ecnpkt_handler(struct cc_var *ccv) delay_ack = 1; /* - * DCTCP responses an ACK immediately when the CE state - * in between this segment and the last segment is not same. + * DCTCP responds with an ACK immediately when the CE state + * in between this segment and the last segment has changed. */ if (ccflag & CCF_IPHDR_CE) { if (!dctcp_data->ce_prev && (ccflag & CCF_DELACK)) @@ -351,8 +358,6 @@ dctcp_ecnpkt_handler(struct cc_var *ccv) if (delay_ack == 0) ccv->flags |= CCF_ACKNOW; - else - ccv->flags &= ~CCF_ACKNOW; } /* _______________________________________________ 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"
