Add support for the experimental Internet-Draft "TCP Alternative Backoff with
ECN (ABE)" proposal to the New Reno congestion control algorithm module. ABE reduces the amount of congestion window reduction in response to ECN-signalled congestion relative to the loss-inferred congestion response. More details about ABE can be found in the Internet-Draft: https://tools.ietf.org/html/draft-ietf-tcpm-alternativebackoff-ecn The implementation introduces four new sysctls: - net.inet.tcp.cc.abe defaults to 0 (disabled) and can be set to non-zero to enable ABE for ECN-enabled TCP connections. - net.inet.tcp.cc.newreno.beta and net.inet.tcp.cc.newreno.beta_ecn set the multiplicative window decrease factor, specified as a percentage, applied to the congestion window in response to a loss-based or ECN-based congestion signal respectively. They default to the values specified in the draft i.e. beta=50 and beta_ecn=80. - net.inet.tcp.cc.abe_frlossreduce defaults to 0 (disabled) and can be set to non-zero to enable the use of standard beta (50% by default) when repairing loss during an ECN-signalled congestion recovery episode. It enables a more conservative congestion response and is provided for the purposes of experimentation as a result of some discussion at IETF 100 in Singapore. The values of beta and beta_ecn can also be set per-connection by way of the TCP_CCALGOOPT TCP-level socket option and the new CC_NEWRENO_BETA or CC_NEWRENO_BETA_ECN CC algo sub-options. Submitted by: Tom Jones <tj@enoti.me> Tested by: Tom Jones <tj@enoti.me>, Grenville Armitage <garmitage@swin.edu.au> Relnotes: Yes Differential Revision: https://reviews.freebsd.org/D11616
This commit is contained in:
parent
2c58a19393
commit
370efe5ac8
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=331214
@ -30,17 +30,69 @@
|
||||
.\"
|
||||
.\" $FreeBSD$
|
||||
.\"
|
||||
.Dd September 15, 2011
|
||||
.Dd March 19, 2018
|
||||
.Dt CC_NEWRENO 4
|
||||
.Os
|
||||
.Sh NAME
|
||||
.Nm cc_newreno
|
||||
.Nd NewReno Congestion Control Algorithm
|
||||
.Sh SYNOPSIS
|
||||
.In netinet/cc/cc_newreno.h
|
||||
.Sh DESCRIPTION
|
||||
The NewReno congestion control algorithm is the default for TCP.
|
||||
Details about the algorithm can be found in RFC5681.
|
||||
.Sh Socket Options
|
||||
The
|
||||
.Nm
|
||||
module supports a number of socket options under TCP_CCALGOOPT (refer to
|
||||
.Xr tcp 4
|
||||
and
|
||||
.Xr moc_cc 9 for details)
|
||||
which can
|
||||
be set with
|
||||
.Xr setsockopt 2
|
||||
and tested with
|
||||
.Xr getsockopt 2 .
|
||||
The
|
||||
.Nm
|
||||
socket options use this structure defined in
|
||||
<sys/netinet/cc/cc_newreno.h>:
|
||||
.Bd -literal
|
||||
struct cc_newreno_opts {
|
||||
int name;
|
||||
uint32_t val;
|
||||
}
|
||||
.Ed
|
||||
.Bl -tag -width ".Va CC_NEWRENO_BETA_ECN"
|
||||
.It Va CC_NEWRENO_BETA
|
||||
Multiplicative window decrease factor, specified as a percentage, applied to
|
||||
the congestion window in response to a congestion signal per: cwnd = (cwnd *
|
||||
CC_NEWRENO_BETA) / 100.
|
||||
Default is 50.
|
||||
.It Va CC_NEWRENO_BETA_ECN
|
||||
Multiplicative window decrease factor, specified as a percentage, applied to
|
||||
the congestion window in response to an ECN congestion signal when
|
||||
.Va net.inet.tcp.cc.abe=1
|
||||
per: cwnd = (cwnd * CC_NEWRENO_BETA_ECN) / 100.
|
||||
Default is 80.
|
||||
.Sh MIB Variables
|
||||
There are currently no tunable MIB variables.
|
||||
The algorithm exposes these variables in the
|
||||
.Va net.inet.tcp.cc.newreno
|
||||
branch of the
|
||||
.Xr sysctl 3
|
||||
MIB:
|
||||
.Bl -tag -width ".Va beta_ecn"
|
||||
.It Va beta
|
||||
Multiplicative window decrease factor, specified as a percentage, applied to
|
||||
the congestion window in response to a congestion signal per: cwnd = (cwnd *
|
||||
beta) / 100.
|
||||
Default is 50.
|
||||
.It Va beta_ecn
|
||||
Multiplicative window decrease factor, specified as a percentage, applied to
|
||||
the congestion window in response to an ECN congestion signal when
|
||||
.Va net.inet.tcp.cc.abe=1
|
||||
per: cwnd = (cwnd * beta_ecn) / 100.
|
||||
Default is 80.
|
||||
.Sh SEE ALSO
|
||||
.Xr cc_chd 4 ,
|
||||
.Xr cc_cubic 4 ,
|
||||
@ -50,6 +102,24 @@ There are currently no tunable MIB variables.
|
||||
.Xr mod_cc 4 ,
|
||||
.Xr tcp 4 ,
|
||||
.Xr mod_cc 9
|
||||
.Rs
|
||||
.%A "Mark Allman"
|
||||
.%A "Vern Paxson"
|
||||
.%A "Ethan Blanton"
|
||||
.%T "TCP Congestion Control"
|
||||
.%O "RFC 5681"
|
||||
.Re
|
||||
.Rs
|
||||
.%A "Naeem Khademi"
|
||||
.%A "Michael Welzl"
|
||||
.%A "Grenville Armitage"
|
||||
.%A "Gorry Fairhurst"
|
||||
.%T "TCP Alternative Backoff with ECN (ABE)"
|
||||
.%R "internet draft"
|
||||
.%D "February 2018"
|
||||
.%N "draft-ietf-tcpm-alternativebackoff-ecn"
|
||||
.%O "work in progress"
|
||||
.Re
|
||||
.Sh ACKNOWLEDGEMENTS
|
||||
Development and testing of this software were made possible in part by grants
|
||||
from the FreeBSD Foundation and Cisco University Research Program Fund at
|
||||
@ -78,5 +148,8 @@ congestion control module was written by
|
||||
and
|
||||
.An David Hayes Aq Mt david.hayes@ieee.org .
|
||||
.Pp
|
||||
Support for TCP ABE was added by
|
||||
.An Tom Jones Aq Mt tj@enoti.me .
|
||||
.Pp
|
||||
This manual page was written by
|
||||
.An Lawrence Stewart Aq Mt lstewart@FreeBSD.org .
|
||||
|
@ -30,7 +30,7 @@
|
||||
.\"
|
||||
.\" $FreeBSD$
|
||||
.\"
|
||||
.Dd January 21, 2016
|
||||
.Dd March 19, 2018
|
||||
.Dt MOD_CC 4
|
||||
.Os
|
||||
.Sh NAME
|
||||
@ -73,7 +73,7 @@ The framework exposes the following variables in the
|
||||
branch of the
|
||||
.Xr sysctl 3
|
||||
MIB:
|
||||
.Bl -tag -width ".Va available"
|
||||
.Bl -tag -width ".Va abe_frlossreduce"
|
||||
.It Va available
|
||||
Read-only list of currently available congestion control algorithms by name.
|
||||
.It Va algorithm
|
||||
@ -83,6 +83,15 @@ When attempting to change the default algorithm, this variable should be set to
|
||||
one of the names listed by the
|
||||
.Va net.inet.tcp.cc.available
|
||||
MIB variable.
|
||||
.It Va abe
|
||||
Enable support for draft-ietf-tcpm-alternativebackoff-ecn,
|
||||
which alters the window decrease factor applied to the congestion window in
|
||||
response to an ECN congestion signal.
|
||||
Refer to individual congestion control man pages to determine if they implement
|
||||
support for ABE and for configuration details.
|
||||
.It Va abe_frlossreduce
|
||||
If non-zero, apply standard beta instead of ABE-beta during ECN-signalled
|
||||
congestion recovery episodes if loss also needs to be repaired.
|
||||
.El
|
||||
.Sh SEE ALSO
|
||||
.Xr cc_cdg 4 ,
|
||||
|
@ -327,3 +327,14 @@ SYSCTL_PROC(_net_inet_tcp_cc, OID_AUTO, algorithm,
|
||||
SYSCTL_PROC(_net_inet_tcp_cc, OID_AUTO, available, CTLTYPE_STRING|CTLFLAG_RD,
|
||||
NULL, 0, cc_list_available, "A",
|
||||
"List available congestion control algorithms");
|
||||
|
||||
VNET_DEFINE(int, cc_do_abe) = 0;
|
||||
SYSCTL_INT(_net_inet_tcp_cc, OID_AUTO, abe, CTLFLAG_VNET | CTLFLAG_RW,
|
||||
&VNET_NAME(cc_do_abe), 0,
|
||||
"Enable draft-ietf-tcpm-alternativebackoff-ecn (TCP Alternative Backoff with ECN)");
|
||||
|
||||
VNET_DEFINE(int, cc_abe_frlossreduce) = 0;
|
||||
SYSCTL_INT(_net_inet_tcp_cc, OID_AUTO, abe_frlossreduce, CTLFLAG_VNET | CTLFLAG_RW,
|
||||
&VNET_NAME(cc_abe_frlossreduce), 0,
|
||||
"Apply standard beta instead of ABE-beta during ECN-signalled congestion "
|
||||
"recovery episodes if loss also needs to be repaired");
|
||||
|
@ -64,6 +64,12 @@ extern struct cc_algo newreno_cc_algo;
|
||||
VNET_DECLARE(struct cc_algo *, default_cc_ptr);
|
||||
#define V_default_cc_ptr VNET(default_cc_ptr)
|
||||
|
||||
VNET_DECLARE(int, cc_do_abe);
|
||||
#define V_cc_do_abe VNET(cc_do_abe)
|
||||
|
||||
VNET_DECLARE(int, cc_abe_frlossreduce);
|
||||
#define V_cc_abe_frlossreduce VNET(cc_abe_frlossreduce)
|
||||
|
||||
/* Define the new net.inet.tcp.cc sysctl tree. */
|
||||
SYSCTL_DECL(_net_inet_tcp_cc);
|
||||
|
||||
|
@ -3,7 +3,7 @@
|
||||
*
|
||||
* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994, 1995
|
||||
* The Regents of the University of California.
|
||||
* Copyright (c) 2007-2008,2010
|
||||
* Copyright (c) 2007-2008,2010,2014
|
||||
* Swinburne University of Technology, Melbourne, Australia.
|
||||
* Copyright (c) 2009-2010 Lawrence Stewart <lstewart@freebsd.org>
|
||||
* Copyright (c) 2010 The FreeBSD Foundation
|
||||
@ -48,6 +48,11 @@
|
||||
* University Research Program Fund at Community Foundation Silicon Valley.
|
||||
* More details are available at:
|
||||
* http://caia.swin.edu.au/urp/newtcp/
|
||||
*
|
||||
* Dec 2014 garmitage@swin.edu.au
|
||||
* Borrowed code fragments from cc_cdg.c to add modifiable beta
|
||||
* via sysctls.
|
||||
*
|
||||
*/
|
||||
|
||||
#include <sys/cdefs.h>
|
||||
@ -69,20 +74,54 @@ __FBSDID("$FreeBSD$");
|
||||
#include <netinet/tcp_var.h>
|
||||
#include <netinet/cc/cc.h>
|
||||
#include <netinet/cc/cc_module.h>
|
||||
#include <netinet/cc/cc_newreno.h>
|
||||
|
||||
static MALLOC_DEFINE(M_NEWRENO, "newreno data",
|
||||
"newreno beta values");
|
||||
|
||||
#define CAST_PTR_INT(X) (*((int*)(X)))
|
||||
|
||||
static int newreno_cb_init(struct cc_var *ccv);
|
||||
static void newreno_ack_received(struct cc_var *ccv, uint16_t type);
|
||||
static void newreno_after_idle(struct cc_var *ccv);
|
||||
static void newreno_cong_signal(struct cc_var *ccv, uint32_t type);
|
||||
static void newreno_post_recovery(struct cc_var *ccv);
|
||||
static int newreno_ctl_output(struct cc_var *ccv, struct sockopt *sopt, void *buf);
|
||||
|
||||
static VNET_DEFINE(uint32_t, newreno_beta) = 50;
|
||||
static VNET_DEFINE(uint32_t, newreno_beta_ecn) = 80;
|
||||
#define V_newreno_beta VNET(newreno_beta)
|
||||
#define V_newreno_beta_ecn VNET(newreno_beta_ecn)
|
||||
|
||||
struct cc_algo newreno_cc_algo = {
|
||||
.name = "newreno",
|
||||
.cb_init = newreno_cb_init,
|
||||
.ack_received = newreno_ack_received,
|
||||
.after_idle = newreno_after_idle,
|
||||
.cong_signal = newreno_cong_signal,
|
||||
.post_recovery = newreno_post_recovery,
|
||||
.ctl_output = newreno_ctl_output,
|
||||
};
|
||||
|
||||
struct newreno {
|
||||
uint32_t beta;
|
||||
uint32_t beta_ecn;
|
||||
};
|
||||
|
||||
int
|
||||
newreno_cb_init(struct cc_var *ccv)
|
||||
{
|
||||
struct newreno *nreno;
|
||||
|
||||
nreno = malloc(sizeof(struct newreno), M_NEWRENO, M_NOWAIT|M_ZERO);
|
||||
if (nreno != NULL) {
|
||||
nreno->beta = V_newreno_beta;
|
||||
nreno->beta_ecn = V_newreno_beta_ecn;
|
||||
}
|
||||
|
||||
return (0);
|
||||
}
|
||||
|
||||
static void
|
||||
newreno_ack_received(struct cc_var *ccv, uint16_t type)
|
||||
{
|
||||
@ -184,27 +223,48 @@ newreno_after_idle(struct cc_var *ccv)
|
||||
static void
|
||||
newreno_cong_signal(struct cc_var *ccv, uint32_t type)
|
||||
{
|
||||
u_int win;
|
||||
struct newreno *nreno;
|
||||
uint32_t cwin, factor;
|
||||
u_int mss;
|
||||
|
||||
factor = V_newreno_beta;
|
||||
nreno = ccv->cc_data;
|
||||
if (nreno != NULL) {
|
||||
if (V_cc_do_abe)
|
||||
factor = (type == CC_ECN ? nreno->beta_ecn: nreno->beta);
|
||||
else
|
||||
factor = nreno->beta;
|
||||
}
|
||||
|
||||
cwin = CCV(ccv, snd_cwnd);
|
||||
mss = CCV(ccv, t_maxseg);
|
||||
|
||||
/* Catch algos which mistakenly leak private signal types. */
|
||||
KASSERT((type & CC_SIGPRIVMASK) == 0,
|
||||
("%s: congestion signal type 0x%08x is private\n", __func__, type));
|
||||
|
||||
win = max(CCV(ccv, snd_cwnd) / 2 / CCV(ccv, t_maxseg), 2) *
|
||||
CCV(ccv, t_maxseg);
|
||||
cwin = max(((uint64_t)cwin * (uint64_t)factor) / (100ULL * (uint64_t)mss),
|
||||
2) * mss;
|
||||
|
||||
switch (type) {
|
||||
case CC_NDUPACK:
|
||||
if (!IN_FASTRECOVERY(CCV(ccv, t_flags))) {
|
||||
if (IN_CONGRECOVERY(CCV(ccv, t_flags) &&
|
||||
V_cc_do_abe && V_cc_abe_frlossreduce)) {
|
||||
CCV(ccv, snd_ssthresh) =
|
||||
((uint64_t)CCV(ccv, snd_ssthresh) *
|
||||
(uint64_t)nreno->beta) /
|
||||
(100ULL * (uint64_t)nreno->beta_ecn);
|
||||
}
|
||||
if (!IN_CONGRECOVERY(CCV(ccv, t_flags)))
|
||||
CCV(ccv, snd_ssthresh) = win;
|
||||
CCV(ccv, snd_ssthresh) = cwin;
|
||||
ENTER_RECOVERY(CCV(ccv, t_flags));
|
||||
}
|
||||
break;
|
||||
case CC_ECN:
|
||||
if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) {
|
||||
CCV(ccv, snd_ssthresh) = win;
|
||||
CCV(ccv, snd_cwnd) = win;
|
||||
CCV(ccv, snd_ssthresh) = cwin;
|
||||
CCV(ccv, snd_cwnd) = cwin;
|
||||
ENTER_CONGRECOVERY(CCV(ccv, t_flags));
|
||||
}
|
||||
break;
|
||||
@ -242,5 +302,75 @@ newreno_post_recovery(struct cc_var *ccv)
|
||||
}
|
||||
}
|
||||
|
||||
int
|
||||
newreno_ctl_output(struct cc_var *ccv, struct sockopt *sopt, void *buf)
|
||||
{
|
||||
struct newreno *nreno;
|
||||
struct cc_newreno_opts *opt;
|
||||
|
||||
if (sopt->sopt_valsize != sizeof(struct cc_newreno_opts))
|
||||
return (EMSGSIZE);
|
||||
|
||||
nreno = ccv->cc_data;
|
||||
opt = buf;
|
||||
|
||||
switch (sopt->sopt_dir) {
|
||||
case SOPT_SET:
|
||||
switch (opt->name) {
|
||||
case CC_NEWRENO_BETA:
|
||||
nreno->beta = opt->val;
|
||||
break;
|
||||
case CC_NEWRENO_BETA_ECN:
|
||||
if (!V_cc_do_abe)
|
||||
return (EACCES);
|
||||
nreno->beta_ecn = opt->val;
|
||||
break;
|
||||
default:
|
||||
return (ENOPROTOOPT);
|
||||
}
|
||||
case SOPT_GET:
|
||||
switch (opt->name) {
|
||||
case CC_NEWRENO_BETA:
|
||||
opt->val = nreno->beta;
|
||||
break;
|
||||
case CC_NEWRENO_BETA_ECN:
|
||||
opt->val = nreno->beta_ecn;
|
||||
break;
|
||||
default:
|
||||
return (ENOPROTOOPT);
|
||||
}
|
||||
default:
|
||||
return (EINVAL);
|
||||
}
|
||||
|
||||
return (0);
|
||||
}
|
||||
|
||||
static int
|
||||
newreno_beta_handler(SYSCTL_HANDLER_ARGS)
|
||||
{
|
||||
if (req->newptr != NULL ) {
|
||||
if (arg1 == &VNET_NAME(newreno_beta_ecn) && !V_cc_do_abe)
|
||||
return (EACCES);
|
||||
if (CAST_PTR_INT(req->newptr) <= 0 || CAST_PTR_INT(req->newptr) > 100)
|
||||
return (EINVAL);
|
||||
}
|
||||
|
||||
return (sysctl_handle_int(oidp, arg1, arg2, req));
|
||||
}
|
||||
|
||||
SYSCTL_DECL(_net_inet_tcp_cc_newreno);
|
||||
SYSCTL_NODE(_net_inet_tcp_cc, OID_AUTO, newreno, CTLFLAG_RW, NULL,
|
||||
"New Reno related settings");
|
||||
|
||||
SYSCTL_PROC(_net_inet_tcp_cc_newreno, OID_AUTO, beta,
|
||||
CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW,
|
||||
&VNET_NAME(newreno_beta), 3, &newreno_beta_handler, "IU",
|
||||
"New Reno beta, specified as number between 1 and 100");
|
||||
|
||||
SYSCTL_PROC(_net_inet_tcp_cc_newreno, OID_AUTO, beta_ecn,
|
||||
CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW,
|
||||
&VNET_NAME(newreno_beta_ecn), 3, &newreno_beta_handler, "IU",
|
||||
"New Reno beta ecn, specified as number between 1 and 100");
|
||||
|
||||
DECLARE_CC_MODULE(newreno, &newreno_cc_algo);
|
||||
|
42
sys/netinet/cc/cc_newreno.h
Normal file
42
sys/netinet/cc/cc_newreno.h
Normal file
@ -0,0 +1,42 @@
|
||||
/*-
|
||||
* Copyright (c) 2017 Tom Jones <tj@enoti.me>
|
||||
* 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.
|
||||
*
|
||||
* $FreeBSD$
|
||||
*/
|
||||
|
||||
#ifndef _CC_NEWRENO_H
|
||||
#define _CC_NEWRENO_H
|
||||
|
||||
#define CCALGONAME_NEWRENO "newreno"
|
||||
|
||||
struct cc_newreno_opts {
|
||||
int name;
|
||||
uint32_t val;
|
||||
};
|
||||
|
||||
#define CC_NEWRENO_BETA 1
|
||||
#define CC_NEWRENO_BETA_ECN 2
|
||||
|
||||
#endif /* _CC_NEWRENO_H */
|
Loading…
Reference in New Issue
Block a user