Index: stable/12/sys/netinet/cc/cc_dctcp.c =================================================================== --- stable/12/sys/netinet/cc/cc_dctcp.c (revision 351994) +++ stable/12/sys/netinet/cc/cc_dctcp.c (revision 351995) @@ -1,466 +1,471 @@ /*- * Copyright (c) 2007-2008 * Swinburne University of Technology, Melbourne, Australia * Copyright (c) 2009-2010 Lawrence Stewart * Copyright (c) 2014 Midori Kato * Copyright (c) 2014 The FreeBSD Foundation * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * An implementation of the DCTCP algorithm for FreeBSD, based on * "Data Center TCP (DCTCP)" by M. Alizadeh, A. Greenberg, D. A. Maltz, * J. Padhye, P. Patel, B. Prabhakar, S. Sengupta, and M. Sridharan., * in ACM Conference on SIGCOMM 2010, New York, USA, * Originally released as the contribution of Microsoft Research project. */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define DCTCP_SHIFT 10 #define MAX_ALPHA_VALUE (1<cc_data; if (CCV(ccv, t_flags) & TF_ECN_PERMIT) { /* * DCTCP doesn't treat receipt of ECN marked packet as a * congestion event. Thus, DCTCP always executes the ACK * processing out of congestion recovery. */ if (IN_CONGRECOVERY(CCV(ccv, t_flags))) { EXIT_CONGRECOVERY(CCV(ccv, t_flags)); newreno_cc_algo.ack_received(ccv, type); ENTER_CONGRECOVERY(CCV(ccv, t_flags)); } else 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; /* Update total bytes. */ dctcp_data->bytes_total += bytes_acked; /* 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 += (bytes_acked - CCV(ccv, t_maxseg)); } else dctcp_data->bytes_ecn += bytes_acked; dctcp_data->ece_prev = 1; } else { if (dctcp_data->ece_prev && bytes_acked > CCV(ccv, t_maxseg)) dctcp_data->bytes_ecn += CCV(ccv, t_maxseg); dctcp_data->ece_prev = 0; } dctcp_data->ece_curr = 0; /* * Update the fraction of marked bytes at the end of * current window size. */ if ((IN_FASTRECOVERY(CCV(ccv, t_flags)) && SEQ_GEQ(ccv->curack, CCV(ccv, snd_recover))) || (!IN_FASTRECOVERY(CCV(ccv, t_flags)) && SEQ_GT(ccv->curack, dctcp_data->save_sndnxt))) dctcp_update_alpha(ccv); } else newreno_cc_algo.ack_received(ccv, type); } static void 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 dctcp_cb_destroy(struct cc_var *ccv) { free(ccv->cc_data, M_dctcp); } static int dctcp_cb_init(struct cc_var *ccv) { struct dctcp *dctcp_data; dctcp_data = malloc(sizeof(struct dctcp), M_dctcp, M_NOWAIT|M_ZERO); if (dctcp_data == NULL) return (ENOMEM); /* Initialize some key variables with sensible defaults. */ dctcp_data->bytes_ecn = 0; dctcp_data->bytes_total = 0; /* * When alpha is set to 0 in the beginning, DCTCP sender transfers as * much data as possible until the value converges which may expand the * queueing delay at the switch. When alpha is set to 1, queueing delay * is kept small. * Throughput-sensitive applications should have alpha = 0 * Latency-sensitive applications should have alpha = 1 * * Note: DCTCP draft suggests initial alpha to be 1 but we've decided to * keep it 0 as default. */ dctcp_data->alpha = V_dctcp_alpha; dctcp_data->save_sndnxt = 0; dctcp_data->ce_prev = 0; dctcp_data->ece_curr = 0; dctcp_data->ece_prev = 0; dctcp_data->num_cong_events = 0; ccv->cc_data = dctcp_data; return (0); } /* * Perform any necessary tasks before we enter congestion recovery. */ 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 dctcp_conn_init(struct cc_var *ccv) { struct dctcp *dctcp_data; dctcp_data = ccv->cc_data; if (CCV(ccv, t_flags) & TF_ECN_PERMIT) dctcp_data->save_sndnxt = CCV(ccv, snd_nxt); } /* * Perform any necessary tasks before we exit congestion recovery. */ 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); } /* * Execute an additional ECN processing using ECN field in IP header and the CWR * bit in TCP header. * * delay_ack == 0 - Delayed ACK disabled * delay_ack == 1 - Delayed ACK enabled */ static void dctcp_ecnpkt_handler(struct cc_var *ccv) { struct dctcp *dctcp_data; uint32_t ccflag; int delay_ack; dctcp_data = ccv->cc_data; ccflag = ccv->flags; 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)) delay_ack = 0; dctcp_data->ce_prev = 1; CCV(ccv, t_flags) |= TF_ECN_SND_ECE; } else { if (dctcp_data->ce_prev && (ccflag & CCF_DELACK)) delay_ack = 0; dctcp_data->ce_prev = 0; CCV(ccv, t_flags) &= ~TF_ECN_SND_ECE; } /* DCTCP sets delayed ack when this segment sets the CWR flag. */ if ((ccflag & CCF_DELACK) && (ccflag & CCF_TCPHDR_CWR)) delay_ack = 1; if (delay_ack == 0) ccv->flags |= CCF_ACKNOW; - else - ccv->flags &= ~CCF_ACKNOW; } /* * Update the fraction of marked bytes represented as 'alpha'. * Also initialize several internal parameters at the end of this function. */ static void dctcp_update_alpha(struct cc_var *ccv) { struct dctcp *dctcp_data; int alpha_prev; dctcp_data = ccv->cc_data; alpha_prev = dctcp_data->alpha; dctcp_data->bytes_total = max(dctcp_data->bytes_total, 1); /* * Update alpha: alpha = (1 - g) * alpha + g * M. * Here: * g is weight factor * recommaded to be set to 1/16 * small g = slow convergence between competitive DCTCP flows * large g = impacts low utilization of bandwidth at switches * M is fraction of marked segments in last RTT * updated every RTT * Alpha must be round to 0 - MAX_ALPHA_VALUE. */ dctcp_data->alpha = ulmin(alpha_prev - (alpha_prev >> V_dctcp_shift_g) + ((uint64_t)dctcp_data->bytes_ecn << (DCTCP_SHIFT - V_dctcp_shift_g)) / dctcp_data->bytes_total, MAX_ALPHA_VALUE); /* Initialize internal parameters for next alpha calculation */ dctcp_data->bytes_ecn = 0; dctcp_data->bytes_total = 0; dctcp_data->save_sndnxt = CCV(ccv, snd_nxt); } static int dctcp_alpha_handler(SYSCTL_HANDLER_ARGS) { uint32_t new; int error; new = V_dctcp_alpha; error = sysctl_handle_int(oidp, &new, 0, req); if (error == 0 && req->newptr != NULL) { if (new > MAX_ALPHA_VALUE) error = EINVAL; else V_dctcp_alpha = new; } return (error); } static int dctcp_shift_g_handler(SYSCTL_HANDLER_ARGS) { uint32_t new; int error; new = V_dctcp_shift_g; error = sysctl_handle_int(oidp, &new, 0, req); if (error == 0 && req->newptr != NULL) { if (new > DCTCP_SHIFT) error = EINVAL; else V_dctcp_shift_g = new; } return (error); } static int dctcp_slowstart_handler(SYSCTL_HANDLER_ARGS) { uint32_t new; int error; new = V_dctcp_slowstart; error = sysctl_handle_int(oidp, &new, 0, req); if (error == 0 && req->newptr != NULL) { if (new > 1) error = EINVAL; else V_dctcp_slowstart = new; } return (error); } SYSCTL_DECL(_net_inet_tcp_cc_dctcp); SYSCTL_NODE(_net_inet_tcp_cc, OID_AUTO, dctcp, CTLFLAG_RW, NULL, "dctcp congestion control related settings"); SYSCTL_PROC(_net_inet_tcp_cc_dctcp, OID_AUTO, alpha, CTLFLAG_VNET|CTLTYPE_UINT|CTLFLAG_RW, &VNET_NAME(dctcp_alpha), 0, &dctcp_alpha_handler, "IU", "dctcp alpha parameter at start of session"); SYSCTL_PROC(_net_inet_tcp_cc_dctcp, OID_AUTO, shift_g, CTLFLAG_VNET|CTLTYPE_UINT|CTLFLAG_RW, &VNET_NAME(dctcp_shift_g), 4, &dctcp_shift_g_handler, "IU", "dctcp shift parameter"); SYSCTL_PROC(_net_inet_tcp_cc_dctcp, OID_AUTO, slowstart, CTLFLAG_VNET|CTLTYPE_UINT|CTLFLAG_RW, &VNET_NAME(dctcp_slowstart), 0, &dctcp_slowstart_handler, "IU", "half CWND reduction after the first slow start"); DECLARE_CC_MODULE(dctcp, &dctcp_cc_algo); Index: stable/12 =================================================================== --- stable/12 (revision 351994) +++ stable/12 (revision 351995) Property changes on: stable/12 ___________________________________________________________________ Modified: svn:mergeinfo ## -0,0 +0,1 ## Merged /head:r350404