From owner-svn-src-all@FreeBSD.ORG Tue Feb 1 06:17:00 2011 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id EC67C106564A; Tue, 1 Feb 2011 06:17:00 +0000 (UTC) (envelope-from lstewart@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id CD4758FC0A; Tue, 1 Feb 2011 06:17:00 +0000 (UTC) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id p116H0cV060696; Tue, 1 Feb 2011 06:17:00 GMT (envelope-from lstewart@svn.freebsd.org) Received: (from lstewart@localhost) by svn.freebsd.org (8.14.3/8.14.3/Submit) id p116H0HN060692; Tue, 1 Feb 2011 06:17:00 GMT (envelope-from lstewart@svn.freebsd.org) Message-Id: <201102010617.p116H0HN060692@svn.freebsd.org> From: Lawrence Stewart Date: Tue, 1 Feb 2011 06:17:00 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r218152 - in head/sys: modules/cc modules/cc/cc_vegas netinet/cc X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 01 Feb 2011 06:17:01 -0000 Author: lstewart Date: Tue Feb 1 06:17:00 2011 New Revision: 218152 URL: http://svn.freebsd.org/changeset/base/218152 Log: Import a clean-room implementation of the VEGAS congestion control algorithm based on the paper "TCP Vegas: end to end congestion avoidance on a global internet" by Brakmo and Peterson. It is implemented as a kernel module compatible with the recently committed modular congestion control framework. VEGAS uses network delay as a congestion indicator and unlike regular loss-based algorithms, attempts to keep the network operating with stable queuing delays and no congestion losses. By keeping network buffers used along the path within a set range, queuing delays are kept low while maintaining high throughput. In collaboration with: David Hayes and Grenville Armitage Sponsored by: FreeBSD Foundation Reviewed by: bz and others along the way MFC after: 3 months Added: head/sys/modules/cc/cc_vegas/ head/sys/modules/cc/cc_vegas/Makefile (contents, props changed) head/sys/netinet/cc/cc_vegas.c (contents, props changed) Modified: head/sys/modules/cc/Makefile Modified: head/sys/modules/cc/Makefile ============================================================================== --- head/sys/modules/cc/Makefile Tue Feb 1 04:39:15 2011 (r218151) +++ head/sys/modules/cc/Makefile Tue Feb 1 06:17:00 2011 (r218152) @@ -1,6 +1,7 @@ # $FreeBSD$ SUBDIR= cc_cubic \ - cc_htcp + cc_htcp \ + cc_vegas .include Added: head/sys/modules/cc/cc_vegas/Makefile ============================================================================== --- /dev/null 00:00:00 1970 (empty, because file is newly added) +++ head/sys/modules/cc/cc_vegas/Makefile Tue Feb 1 06:17:00 2011 (r218152) @@ -0,0 +1,9 @@ +# $FreeBSD$ + +.include + +.PATH: ${.CURDIR}/../../../netinet/cc +KMOD= cc_vegas +SRCS= cc_vegas.c + +.include Added: head/sys/netinet/cc/cc_vegas.c ============================================================================== --- /dev/null 00:00:00 1970 (empty, because file is newly added) +++ head/sys/netinet/cc/cc_vegas.c Tue Feb 1 06:17:00 2011 (r218152) @@ -0,0 +1,308 @@ +/*- + * Copyright (c) 2009-2010 + * Swinburne University of Technology, Melbourne, Australia + * Copyright (c) 2010 Lawrence Stewart + * Copyright (c) 2010-2011 The FreeBSD Foundation + * All rights reserved. + * + * This software was developed at the Centre for Advanced Internet + * Architectures, Swinburne University, by David Hayes and Lawrence Stewart, + * made possible in part by a grant from the Cisco University Research Program + * Fund at Community Foundation Silicon Valley. + * + * Portions of this software were developed at the Centre for Advanced Internet + * Architectures, Swinburne University of Technology, Melbourne, Australia by + * David Hayes under sponsorship from the FreeBSD Foundation. + * + * 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 Vegas congestion control algorithm for FreeBSD, + * based on L. S. Brakmo and L. L. Peterson, "TCP Vegas: end to end congestion + * avoidance on a global internet", IEEE J. Sel. Areas Commun., vol. 13, no. 8, + * pp. 1465-1480, Oct. 1995. The original Vegas duplicate ack policy has not + * been implemented, since clock ticks are not as course as they were (i.e. + * 500ms) when Vegas was designed. Also, packets are timed once per RTT as in + * the original paper. + * + * Originally released as part of the NewTCP research project at Swinburne + * University's Centre for Advanced Internet Architectures, Melbourne, + * Australia, which was made possible in part by a grant from the Cisco + * University Research Program Fund at Community Foundation Silicon Valley. More + * details are available at: + * http://caia.swin.edu.au/urp/newtcp/ + */ + +#include +__FBSDID("$FreeBSD$"); + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include +#include +#include +#include + +#include + +#include + +#define CAST_PTR_INT(X) (*((int*)(X))) + +/* + * Private signal type for rate based congestion signal. + * See for appropriate bit-range to use for private signals. + */ +#define CC_VEGAS_RATE 0x01000000 + +static void vegas_ack_received(struct cc_var *ccv, uint16_t ack_type); +static void vegas_cb_destroy(struct cc_var *ccv); +static int vegas_cb_init(struct cc_var *ccv); +static void vegas_cong_signal(struct cc_var *ccv, uint32_t signal_type); +static void vegas_conn_init(struct cc_var *ccv); +static int vegas_mod_init(void); + +struct vegas { + int slow_start_toggle; +}; + +static int32_t ertt_id; + +static VNET_DEFINE(uint32_t, vegas_alpha) = 1; +static VNET_DEFINE(uint32_t, vegas_beta) = 3; +#define V_vegas_alpha VNET(vegas_alpha) +#define V_vegas_beta VNET(vegas_beta) + +MALLOC_DECLARE(M_VEGAS); +MALLOC_DEFINE(M_VEGAS, "vegas data", + "Per connection data required for the Vegas congestion control algorithm"); + +struct cc_algo vegas_cc_algo = { + .name = "vegas", + .ack_received = vegas_ack_received, + .cb_destroy = vegas_cb_destroy, + .cb_init = vegas_cb_init, + .cong_signal = vegas_cong_signal, + .conn_init = vegas_conn_init, + .mod_init = vegas_mod_init +}; + +/* + * The vegas window adjustment is done once every RTT, as indicated by the + * ERTT_NEW_MEASUREMENT flag. This flag is reset once the new measurment data + * has been used. + */ +static void +vegas_ack_received(struct cc_var *ccv, uint16_t ack_type) +{ + struct ertt *e_t; + struct vegas *vegas_data; + long actual_tx_rate, expected_tx_rate, ndiff; + + e_t = khelp_get_osd(CCV(ccv, osd), ertt_id); + vegas_data = ccv->cc_data; + + if (e_t->flags & ERTT_NEW_MEASUREMENT) { /* Once per RTT. */ + if (e_t->minrtt && e_t->markedpkt_rtt) { + expected_tx_rate = e_t->marked_snd_cwnd / e_t->minrtt; + actual_tx_rate = e_t->bytes_tx_in_marked_rtt / + e_t->markedpkt_rtt; + ndiff = (expected_tx_rate - actual_tx_rate) * + e_t->minrtt / CCV(ccv, t_maxseg); + + if (ndiff < V_vegas_alpha) { + if (CCV(ccv, snd_cwnd) <= + CCV(ccv, snd_ssthresh)) { + vegas_data->slow_start_toggle = + vegas_data->slow_start_toggle ? + 0 : 1; + } else { + vegas_data->slow_start_toggle = 0; + CCV(ccv, snd_cwnd) = + min(CCV(ccv, snd_cwnd) + + CCV(ccv, t_maxseg), + TCP_MAXWIN << CCV(ccv, snd_scale)); + } + } else if (ndiff > V_vegas_beta) { + /* Rate-based congestion. */ + vegas_cong_signal(ccv, CC_VEGAS_RATE); + vegas_data->slow_start_toggle = 0; + } + } + e_t->flags &= ~ERTT_NEW_MEASUREMENT; + } + + if (vegas_data->slow_start_toggle) + newreno_cc_algo.ack_received(ccv, ack_type); +} + +static void +vegas_cb_destroy(struct cc_var *ccv) +{ + + if (ccv->cc_data != NULL) + free(ccv->cc_data, M_VEGAS); +} + +static int +vegas_cb_init(struct cc_var *ccv) +{ + struct vegas *vegas_data; + + vegas_data = malloc(sizeof(struct vegas), M_VEGAS, M_NOWAIT); + + if (vegas_data == NULL) + return (ENOMEM); + + vegas_data->slow_start_toggle = 1; + ccv->cc_data = vegas_data; + + return (0); +} + +/* + * If congestion has been triggered triggered by the Vegas measured rates, it is + * handled here, otherwise it falls back to newreno's congestion handling. + */ +static void +vegas_cong_signal(struct cc_var *ccv, uint32_t signal_type) +{ + struct vegas *vegas_data; + int presignalrecov; + + vegas_data = ccv->cc_data; + + if (IN_RECOVERY(CCV(ccv, t_flags))) + presignalrecov = 1; + else + presignalrecov = 0; + + switch(signal_type) { + case CC_VEGAS_RATE: + if (!IN_RECOVERY(CCV(ccv, t_flags))) { + CCV(ccv, snd_cwnd) = max(2 * CCV(ccv, t_maxseg), + CCV(ccv, snd_cwnd) - CCV(ccv, t_maxseg)); + if (CCV(ccv, snd_cwnd) < CCV(ccv, snd_ssthresh)) + /* Exit slow start. */ + CCV(ccv, snd_ssthresh) = CCV(ccv, snd_cwnd); + } + break; + + default: + newreno_cc_algo.cong_signal(ccv, signal_type); + } + + if (IN_RECOVERY(CCV(ccv, t_flags)) && !presignalrecov) + vegas_data->slow_start_toggle = + (CCV(ccv, snd_cwnd) < CCV(ccv, snd_ssthresh)) ? 1 : 0; +} + +static void +vegas_conn_init(struct cc_var *ccv) +{ + struct vegas *vegas_data; + + vegas_data = ccv->cc_data; + vegas_data->slow_start_toggle = 1; +} + +static int +vegas_mod_init(void) +{ + + ertt_id = khelp_get_id("ertt"); + if (ertt_id <= 0) { + printf("%s: h_ertt module not found\n", __func__); + return (ENOENT); + } + + vegas_cc_algo.after_idle = newreno_cc_algo.after_idle; + vegas_cc_algo.post_recovery = newreno_cc_algo.post_recovery; + + return (0); +} + +static int +vegas_alpha_handler(SYSCTL_HANDLER_ARGS) +{ + int error; + uint32_t new; + + new = V_vegas_alpha; + error = sysctl_handle_int(oidp, &new, 0, req); + if (error == 0 && req->newptr != NULL) { + if (CAST_PTR_INT(req->newptr) < 1 || + CAST_PTR_INT(req->newptr) > V_vegas_beta) + error = EINVAL; + else + V_vegas_alpha = new; + } + + return (error); +} + +static int +vegas_beta_handler(SYSCTL_HANDLER_ARGS) +{ + int error; + uint32_t new; + + new = V_vegas_beta; + error = sysctl_handle_int(oidp, &new, 0, req); + if (error == 0 && req->newptr != NULL) { + if (CAST_PTR_INT(req->newptr) < 1 || + CAST_PTR_INT(req->newptr) < V_vegas_alpha) + error = EINVAL; + else + V_vegas_beta = new; + } + + return (error); +} + +SYSCTL_DECL(_net_inet_tcp_cc_vegas); +SYSCTL_NODE(_net_inet_tcp_cc, OID_AUTO, vegas, CTLFLAG_RW, NULL, + "Vegas related settings"); + +SYSCTL_VNET_PROC(_net_inet_tcp_cc_vegas, OID_AUTO, alpha, + CTLTYPE_UINT|CTLFLAG_RW, &VNET_NAME(vegas_alpha), 1, &vegas_alpha_handler, + "IU", "vegas alpha, specified as number of \"buffers\" (0 < alpha < beta)"); + +SYSCTL_VNET_PROC(_net_inet_tcp_cc_vegas, OID_AUTO, beta, + CTLTYPE_UINT|CTLFLAG_RW, &VNET_NAME(vegas_beta), 3, &vegas_beta_handler, + "IU", "vegas beta, specified as number of \"buffers\" (0 < alpha < beta)"); + +DECLARE_CC_MODULE(vegas, &vegas_cc_algo); +MODULE_DEPEND(vegas, ertt, 1, 1, 1);