[PATCH] Implementation of draft-ietf-tcpm-newcwv-06
Tom Jones
jones at sdf.org
Fri Aug 1 14:19:02 UTC 2014
On Mon, Jun 30, 2014 at 09:53:59PM +0100, Tom Jones wrote:
> On Mon, Jun 30, 2014 at 12:29:44PM -0700, Adrian Chadd wrote:
> > Hi!
> >
> > Cool! Would you mind throwing it into a bugzilla ticket so it's not
> > lost and it can be assigned for some review?
> >
> > http://bugs.freebsd.org/submit/
>
> Done.
> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=191520
>
> > Is there any benefit in hanging this state off of it as a pointer to
> > some other struct, rather than having it in the tcpcb? Is it always
> > going to be used?
>
> The draft recommends newcwv be used as a default, so there is a chance it will
> always be around. What would the impact to performance be by moving the state
> out into a struct?
I have updated the patch to move the new variable introduced with newcwv into a
struct within the tcpcb.
--
Tom | I don't see how we are going to build the dystopian megapoli
@adventureloop | we were promised in 80s and early 90s cyberpunk fiction if
adventurist.me | you guys keep complaining.
:wq
-------------- next part --------------
Index: sys/conf/files
===================================================================
--- sys/conf/files (revision 269231)
+++ sys/conf/files (working copy)
@@ -3383,6 +3383,7 @@
netinet/tcp_sack.c optional inet | inet6
netinet/tcp_subr.c optional inet | inet6
netinet/tcp_syncache.c optional inet | inet6
+netinet/tcp_newcwv.c optional inet | inet6
netinet/tcp_timer.c optional inet | inet6
netinet/tcp_timewait.c optional inet | inet6
netinet/tcp_usrreq.c optional inet | inet6
Index: sys/netinet/tcp_input.c
===================================================================
--- sys/netinet/tcp_input.c (revision 269231)
+++ sys/netinet/tcp_input.c (working copy)
@@ -105,6 +105,7 @@
#include <netinet6/tcp6_var.h>
#include <netinet/tcpip.h>
#include <netinet/tcp_syncache.h>
+#include <netinet/tcp_newcwv.h>
#ifdef TCPDEBUG
#include <netinet/tcp_debug.h>
#endif /* TCPDEBUG */
@@ -174,6 +175,11 @@
&VNET_NAME(tcp_abc_l_var), 2,
"Cap the max cwnd increment during slow-start to this number of segments");
+VNET_DEFINE(int, tcp_do_newcwv) = 0;
+SYSCTL_VNET_INT(_net_inet_tcp, OID_AUTO, newcwv, CTLFLAG_RW,
+ &VNET_NAME(tcp_do_newcwv), 0,
+ "Enable draft-ietf-tcpm-newcwv-06 (New Congestion Window Validation)");
+
static SYSCTL_NODE(_net_inet_tcp, OID_AUTO, ecn, CTLFLAG_RW, 0, "TCP ECN");
VNET_DEFINE(int, tcp_do_ecn) = 0;
@@ -285,9 +291,12 @@
INP_WLOCK_ASSERT(tp->t_inpcb);
tp->ccv->bytes_this_ack = BYTES_THIS_ACK(tp, th);
- if (tp->snd_cwnd <= tp->snd_wnd)
+ /* draft-ietf-tcpm-newcwv relaxes conditions for growing cwnd */
+ if (tp->snd_cwnd <= tp->snd_wnd ||
+ (V_tcp_do_newcwv && tp->newcwv.pipeack >= (tp->snd_cwnd >> 1)) ) {
tp->ccv->flags |= CCF_CWND_LIMITED;
- else
+ tp->newcwv.cwnd_valid_ts = ticks;
+ } else
tp->ccv->flags &= ~CCF_CWND_LIMITED;
if (type == CC_ACK) {
@@ -309,6 +318,12 @@
tp->ccv->curack = th->th_ack;
CC_ALGO(tp)->ack_received(tp->ccv, type);
}
+
+ /*
+ * update draft-ietf-newcwv-06 pipeack
+ */
+ if(V_tcp_do_newcwv && !IN_FASTRECOVERY(tp->t_flags))
+ tcp_newcwv_update_pipeack(tp);
}
static void inline
@@ -378,6 +393,12 @@
tp->snd_cwnd = 4 * tp->t_maxseg;
}
+ /*
+ * Initialise NewCWV state
+ */
+ tp->newcwv.init_cwnd = tp->snd_cwnd;
+ tcp_newcwv_reset(tp);
+
if (CC_ALGO(tp)->conn_init != NULL)
CC_ALGO(tp)->conn_init(tp->ccv);
}
@@ -426,6 +447,11 @@
tp->t_badrxtwin = 0;
break;
}
+
+ if (V_tcp_do_newcwv &&
+ (type == CC_NDUPACK || type == CC_ECN) &&
+ tp->newcwv.pipeack <= (tp->snd_cwnd >> 1) )
+ tcp_newcwv_enter_recovery(tp);
if (CC_ALGO(tp)->cong_signal != NULL) {
if (th != NULL)
@@ -447,6 +473,13 @@
}
/* XXXLAS: EXIT_RECOVERY ? */
tp->t_bytes_acked = 0;
+
+ if(V_tcp_do_newcwv) {
+ if(tp->newcwv.loss_flight_size)
+ tcp_newcwv_end_recovery(tp);
+ tcp_newcwv_reset(tp);
+ }
+ tp->newcwv.loss_flight_size = 0;
}
#ifdef TCP_SIGNATURE
Index: sys/netinet/tcp_output.c
===================================================================
--- sys/netinet/tcp_output.c (revision 269231)
+++ sys/netinet/tcp_output.c (working copy)
@@ -74,6 +74,7 @@
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <netinet/tcpip.h>
+#include <netinet/tcp_newcwv.h>
#ifdef TCPDEBUG
#include <netinet/tcp_debug.h>
#endif
@@ -691,6 +692,10 @@
#endif
hdrlen = sizeof (struct tcpiphdr);
+ /* Trigger the newcwv timer */
+ if(V_tcp_do_newcwv)
+ tcp_newcwv_datalim_closedown(tp);
+
/*
* Compute options for segment.
* We only have to care about SYN and established connection
Index: sys/netinet/tcp_subr.c
===================================================================
--- sys/netinet/tcp_subr.c (revision 269231)
+++ sys/netinet/tcp_subr.c (working copy)
@@ -800,6 +800,7 @@
tp->t_flags = (TF_REQ_SCALE|TF_REQ_TSTMP);
if (V_tcp_do_sack)
tp->t_flags |= TF_SACK_PERMIT;
+
TAILQ_INIT(&tp->snd_holes);
tp->t_inpcb = inp; /* XXX */
/*
Index: sys/netinet/tcp_var.h
===================================================================
--- sys/netinet/tcp_var.h (revision 269231)
+++ sys/netinet/tcp_var.h (working copy)
@@ -172,6 +172,22 @@
int t_sndzerowin; /* zero-window updates sent */
u_int t_badrxtwin; /* window for retransmit recovery */
u_char snd_limited; /* segments limited transmitted */
+/* NewCWV releated state */
+ struct {
+ u_int32_t pipeack;
+ u_int32_t psp; /* pipeack sampling period */
+
+ u_int32_t head;
+ u_int32_t psample[4]; /* pipe ack samples */
+ u_int32_t time_stamp[4]; /* time stamp samples */
+ u_int32_t prev_snd_una; /* previous snd_una in this sampe */
+ u_int32_t prev_snd_nxt; /* previous snd_nxt in this sampe */
+
+ u_int32_t loss_flight_size; /* flightsize at loss detection */
+ u_int32_t prior_retrans; /* Retransmission before going into FR */
+ u_int32_t cwnd_valid_ts; /*last time cwnd was found valid */
+ u_int32_t init_cwnd; /* The inital cwnd */
+ } newcwv;
/* SACK related state */
int snd_numholes; /* number of holes seen by sender */
TAILQ_HEAD(sackhole_head, sackhole) snd_holes;
@@ -605,6 +621,7 @@
VNET_DECLARE(int, path_mtu_discovery);
VNET_DECLARE(int, tcp_do_rfc3465);
VNET_DECLARE(int, tcp_abc_l_var);
+VNET_DECLARE(int, tcp_do_newcwv);
#define V_tcb VNET(tcb)
#define V_tcbinfo VNET(tcbinfo)
#define V_tcp_mssdflt VNET(tcp_mssdflt)
@@ -617,6 +634,7 @@
#define V_path_mtu_discovery VNET(path_mtu_discovery)
#define V_tcp_do_rfc3465 VNET(tcp_do_rfc3465)
#define V_tcp_abc_l_var VNET(tcp_abc_l_var)
+#define V_tcp_do_newcwv VNET(tcp_do_newcwv)
VNET_DECLARE(int, tcp_do_sack); /* SACK enabled/disabled */
VNET_DECLARE(int, tcp_sc_rst_sock_fail); /* RST on sock alloc failure */
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