git: e97522a1b7ea - stable/13 - tcp: remove unused t_rttbest

The branch stable/13 has been updated by tuexen:

URL: https://cgit.FreeBSD.org/src/commit/?id=e97522a1b7ea023961d604221eb38960fd170fa9

commit e97522a1b7ea023961d604221eb38960fd170fa9
Author:     Michael Tuexen <tuexen@FreeBSD.org>
AuthorDate: 2022-11-16 10:22:13 +0000
Commit:     Michael Tuexen <tuexen@FreeBSD.org>
CommitDate: 2023-02-02 00:02:30 +0000

    tcp: remove unused t_rttbest
    
    No functional change intended.
    
    Reviewed by:            rscheff@
    Sponsored by:           Netflix, Inc.
    Differential Revision:  https://reviews.freebsd.org/D37401
    
    (cherry picked from commit bd4f986644b3804e19b92d39f1f90ffabff83e14)
---
 sys/netinet/tcp_input.c       | 4 ----
 sys/netinet/tcp_stacks/bbr.c  | 3 ---
 sys/netinet/tcp_stacks/rack.c | 3 ---
 sys/netinet/tcp_usrreq.c      | 5 ++---
 sys/netinet/tcp_var.h         | 2 --
 5 files changed, 2 insertions(+), 15 deletions(-)

diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
index 94e9d0b71cb8..1c2fe014c7f3 100644
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -410,7 +410,6 @@ cc_conn_init(struct tcpcb *tp)
 
 	if (tp->t_srtt == 0 && (rtt = metrics.rmx_rtt)) {
 		tp->t_srtt = rtt;
-		tp->t_rttbest = tp->t_srtt + TCP_RTT_SCALE;
 		TCPSTAT_INC(tcps_usedrtt);
 		if (metrics.rmx_rttvar) {
 			tp->t_rttvar = metrics.rmx_rttvar;
@@ -3642,8 +3641,6 @@ tcp_xmit_timer(struct tcpcb *tp, int rtt)
 		delta -= tp->t_rttvar >> (TCP_RTTVAR_SHIFT - TCP_DELTA_SHIFT);
 		if ((tp->t_rttvar += delta) <= 0)
 			tp->t_rttvar = 1;
-		if (tp->t_rttbest > tp->t_srtt + tp->t_rttvar)
-		    tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
 	} else {
 		/*
 		 * No rtt measurement yet - use the unsmoothed rtt.
@@ -3652,7 +3649,6 @@ tcp_xmit_timer(struct tcpcb *tp, int rtt)
 		 */
 		tp->t_srtt = rtt << TCP_RTT_SHIFT;
 		tp->t_rttvar = rtt << (TCP_RTTVAR_SHIFT - 1);
-		tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
 	}
 	tp->t_rtttime = 0;
 	tp->t_rxtshift = 0;
diff --git a/sys/netinet/tcp_stacks/bbr.c b/sys/netinet/tcp_stacks/bbr.c
index 42c66ac57891..1b4abfb6f5c4 100644
--- a/sys/netinet/tcp_stacks/bbr.c
+++ b/sys/netinet/tcp_stacks/bbr.c
@@ -6395,8 +6395,6 @@ tcp_bbr_xmit_timer_commit(struct tcp_bbr *bbr, struct tcpcb *tp, uint32_t cts)
 		tp->t_rttvar += delta;
 		if (tp->t_rttvar <= 0)
 			tp->t_rttvar = 1;
-		if (tp->t_rttbest > tp->t_srtt + tp->t_rttvar)
-			tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
 	} else {
 		/*
 		 * No rtt measurement yet - use the unsmoothed rtt. Set the
@@ -6405,7 +6403,6 @@ tcp_bbr_xmit_timer_commit(struct tcp_bbr *bbr, struct tcpcb *tp, uint32_t cts)
 		 */
 		tp->t_srtt = rtt_ticks << TCP_RTT_SHIFT;
 		tp->t_rttvar = rtt_ticks << (TCP_RTTVAR_SHIFT - 1);
-		tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
 	}
 	KMOD_TCPSTAT_INC(tcps_rttupdated);
 	tp->t_rttupdated++;
diff --git a/sys/netinet/tcp_stacks/rack.c b/sys/netinet/tcp_stacks/rack.c
index 162b1c928ef7..ead81528ace5 100644
--- a/sys/netinet/tcp_stacks/rack.c
+++ b/sys/netinet/tcp_stacks/rack.c
@@ -7737,8 +7737,6 @@ tcp_rack_xmit_timer_commit(struct tcp_rack *rack, struct tcpcb *tp)
 		tp->t_rttvar += (delta >> 3);
 		if (tp->t_rttvar <= 0)
 			tp->t_rttvar = 1;
-		if (tp->t_rttbest > tp->t_srtt + tp->t_rttvar)
-			tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
 	} else {
 		/*
 		 * No rtt measurement yet - use the unsmoothed rtt. Set the
@@ -7747,7 +7745,6 @@ tcp_rack_xmit_timer_commit(struct tcp_rack *rack, struct tcpcb *tp)
 		 */
 		tp->t_srtt = rtt;
 		tp->t_rttvar = rtt >> 1;
-		tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
 	}
 	rack->rc_srtt_measure_made = 1;
 	KMOD_TCPSTAT_INC(tcps_rttupdated);
diff --git a/sys/netinet/tcp_usrreq.c b/sys/netinet/tcp_usrreq.c
index 74bf2925870f..0706e55f439b 100644
--- a/sys/netinet/tcp_usrreq.c
+++ b/sys/netinet/tcp_usrreq.c
@@ -2919,9 +2919,8 @@ db_print_tcpcb(struct tcpcb *tp, const char *name, int indent)
 	    tp->t_rxtcur, tp->t_maxseg, tp->t_srtt);
 
 	db_print_indent(indent);
-	db_printf("t_rttvar: %d   t_rxtshift: %d   t_rttmin: %u   "
-	    "t_rttbest: %u\n", tp->t_rttvar, tp->t_rxtshift, tp->t_rttmin,
-	    tp->t_rttbest);
+	db_printf("t_rttvar: %d   t_rxtshift: %d   t_rttmin: %u\n",
+	    tp->t_rttvar, tp->t_rxtshift, tp->t_rttmin);
 
 	db_print_indent(indent);
 	db_printf("t_rttupdated: %lu   max_sndwnd: %u   t_softerror: %d\n",
diff --git a/sys/netinet/tcp_var.h b/sys/netinet/tcp_var.h
index 4a05f0f5ab2e..2474f3787903 100644
--- a/sys/netinet/tcp_var.h
+++ b/sys/netinet/tcp_var.h
@@ -212,8 +212,6 @@ struct tcpcb {
 	int	t_blackhole_exit;	/* when to exit blackhole detection */
 	u_int	t_rttmin;		/* minimum rtt allowed */
 
-	u_int	t_rttbest;		/* best rtt we've seen */
-
 	int	t_softerror;		/* possible error not yet reported */
 	uint32_t  max_sndwnd;		/* largest window peer has offered */
 	/* Cache line 5 */