The branch main has been updated by rrs:
URL:
https://cgit.FreeBSD.org/src/commit/?id=f3bba8cd62f2ddcacba7d9c36a2cc21b1fe11968
commit f3bba8cd62f2ddcacba7d9c36a2cc21b1fe11968
Author: Randall Stewart <r...@freebsd.org>
AuthorDate: 2025-06-15 09:02:39 +0000
Commit: Randall Stewart <r...@freebsd.org>
CommitDate: 2025-06-15 09:02:39 +0000
TCP without LRO doing static pacing does not always pace as expected.
cause a surprise extra packet i.e. the burst limit being overstepped and
another one where
the burst limit is under stepped. This patch fixes those errors.
Reported by: tuexen
Reviewed by: tuexen
Differential Revision: <https://reviews.freebsd.org/D50858>
---
sys/netinet/tcp_stacks/rack.c | 56 +++++++++++++++++++++++++++----------------
1 file changed, 36 insertions(+), 20 deletions(-)
diff --git a/sys/netinet/tcp_stacks/rack.c b/sys/netinet/tcp_stacks/rack.c
index cb4e22401c12..1d4bc3124058 100644
--- a/sys/netinet/tcp_stacks/rack.c
+++ b/sys/netinet/tcp_stacks/rack.c
@@ -17178,6 +17178,12 @@ rack_log_pacing_delay_calc (struct tcp_rack *rack,
uint32_t len, uint32_t slot,
log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ss;
log.u_bbr.cwnd_gain <<= 1;
log.u_bbr.cwnd_gain |= rack->rc_gp_saw_ca;
+ log.u_bbr.cwnd_gain <<= 1;
+ log.u_bbr.cwnd_gain |= rack->use_fixed_rate;
+ log.u_bbr.cwnd_gain <<= 1;
+ log.u_bbr.cwnd_gain |= rack->rc_always_pace;
+ log.u_bbr.cwnd_gain <<= 1;
+ log.u_bbr.cwnd_gain |= rack->gp_ready;
log.u_bbr.bbr_substate = quality;
log.u_bbr.bbr_state = rack->dgp_on;
log.u_bbr.bbr_state <<= 1;
@@ -17539,8 +17545,8 @@ rack_get_pacing_delay(struct tcp_rack *rack, struct
tcpcb *tp, uint32_t len, str
rack->r_ctl.rc_last_us_rtt,
88, __LINE__, NULL, gain);
}
- if ((bw_est == 0) || (rate_wanted == 0) ||
- ((rack->gp_ready == 0) && (rack->use_fixed_rate == 0))) {
+ if (((bw_est == 0) || (rate_wanted == 0) || (rack->gp_ready ==
0)) &&
+ (rack->use_fixed_rate == 0)) {
/*
* No way yet to make a b/w estimate or
* our raise is set incorrectly.
@@ -19039,7 +19045,7 @@ rack_sndbuf_autoscale(struct tcp_rack *rack)
static int
rack_fast_output(struct tcpcb *tp, struct tcp_rack *rack, uint64_t ts_val,
- uint32_t cts, uint32_t ms_cts, struct timeval *tv, long
tot_len, int *send_err)
+ uint32_t cts, uint32_t ms_cts, struct timeval *tv, long
*tot_len, int *send_err, int line)
{
/*
* Enter to do fast output. We are given that the sched_pin is
@@ -19212,7 +19218,7 @@ again:
}
if (rack->r_ctl.fsb.rfo_apply_push &&
(len == rack->r_ctl.fsb.left_to_send)) {
- tcp_set_flags(th, flags | TH_PUSH);
+ flags |= TH_PUSH;
add_flag |= RACK_HAD_PUSH;
}
if ((m->m_next == NULL) || (len <= 0)){
@@ -19391,11 +19397,11 @@ again:
log.u_bbr.inflight = ctf_flight_size(rack->rc_tp,
rack->r_ctl.rc_sacked);
log.u_bbr.flex5 = log.u_bbr.inflight;
log.u_bbr.lt_epoch = rack->r_ctl.cwnd_to_use;
- log.u_bbr.delivered = 0;
+ log.u_bbr.delivered = rack->r_ctl.fsb.left_to_send;
log.u_bbr.rttProp = 0;
log.u_bbr.delRate = rack->r_must_retran;
log.u_bbr.delRate <<= 1;
- log.u_bbr.pkt_epoch = __LINE__;
+ log.u_bbr.pkt_epoch = line;
/* For fast output no retrans so just inflight and how many mss
we send */
log.u_bbr.flex5 = log.u_bbr.inflight;
log.u_bbr.bbr_substate = (uint8_t)((len + segsiz - 1)/segsiz);
@@ -19468,7 +19474,7 @@ again:
tcp_account_for_send(tp, len, 0, 0, rack->r_ctl.fsb.hw_tls);
rack->forced_ack = 0; /* If we send something zap the FA flag */
- tot_len += len;
+ *tot_len += len;
if ((tp->t_flags & TF_GPUTINPROG) == 0)
rack_start_gp_measurement(tp, rack, tp->snd_max, sb_offset);
tp->snd_max += len;
@@ -19504,6 +19510,7 @@ again:
}
if ((rack->r_ctl.fsb.left_to_send >= segsiz) &&
(max_val > len) &&
+ (*tot_len < rack->r_ctl.rc_pace_max_segs) &&
(tso == 0)) {
max_val -= len;
len = segsiz;
@@ -19515,14 +19522,14 @@ again:
}
tp->t_flags &= ~(TF_ACKNOW | TF_DELACK);
counter_u64_add(rack_fto_send, 1);
- slot = rack_get_pacing_delay(rack, tp, tot_len, NULL, segsiz, __LINE__);
- rack_start_hpts_timer(rack, tp, cts, slot, tot_len, 0);
+ slot = rack_get_pacing_delay(rack, tp, *tot_len, NULL, segsiz,
__LINE__);
+ rack_start_hpts_timer(rack, tp, cts, slot, *tot_len, 0);
#ifdef TCP_ACCOUNTING
crtsc = get_cyclecount();
if (tp->t_flags2 & TF2_TCP_ACCOUNTING) {
tp->tcp_cnt_counters[SND_OUT_DATA] += cnt_thru;
tp->tcp_proc_time[SND_OUT_DATA] += (crtsc - ts_val);
- tp->tcp_cnt_counters[CNT_OF_MSS_OUT] += ((tot_len + segsiz - 1)
/ segsiz);
+ tp->tcp_cnt_counters[CNT_OF_MSS_OUT] += ((*tot_len + segsiz -
1) / segsiz);
}
sched_unpin();
#endif
@@ -19884,20 +19891,36 @@ rack_output(struct tcpcb *tp)
TCPS_HAVEESTABLISHED(tp->t_state)) {
rack_set_state(tp, rack);
}
+ segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
+ minseg = segsiz;
+ if (rack->r_ctl.rc_pace_max_segs == 0)
+ pace_max_seg = rack->rc_user_set_max_segs * segsiz;
+ else
+ pace_max_seg = rack->r_ctl.rc_pace_max_segs;
if ((rack->r_fast_output) &&
(doing_tlp == 0) &&
(tp->rcv_numsacks == 0)) {
int ret;
error = 0;
- ret = rack_fast_output(tp, rack, ts_val, cts, ms_cts, &tv,
tot_len_this_send, &error);
- if (ret >= 0)
+ ret = rack_fast_output(tp, rack, ts_val, cts, ms_cts, &tv,
&tot_len_this_send, &error, __LINE__);
+ if (ret > 0)
return(ret);
else if (error) {
inp = rack->rc_inp;
so = inp->inp_socket;
sb = &so->so_snd;
goto nomore;
+ } else {
+ /* Return == 0, if there is more we can send tot_len
wise fall through and send */
+ if (tot_len_this_send >= pace_max_seg)
+ return (ret);
+#ifdef TCP_ACCOUNTING
+ /* We need to re-pin since fast_output un-pined */
+ sched_pin();
+ ts_val = get_cyclecount();
+#endif
+ /* Fall back out so we can send any more that may bring
us to pace_max_seg */
}
}
inp = rack->rc_inp;
@@ -20004,12 +20027,6 @@ again:
ms_cts = tcp_tv_to_mssectick(&tv);
tso = 0;
mtu = 0;
- segsiz = min(ctf_fixed_maxseg(tp), rack->r_ctl.rc_pace_min_segs);
- minseg = segsiz;
- if (rack->r_ctl.rc_pace_max_segs == 0)
- pace_max_seg = rack->rc_user_set_max_segs * segsiz;
- else
- pace_max_seg = rack->r_ctl.rc_pace_max_segs;
if (TCPS_HAVEESTABLISHED(tp->t_state) &&
(rack->r_ctl.pcm_max_seg == 0)) {
/*
@@ -21593,7 +21610,6 @@ send:
flags |= TH_PUSH;
add_flag |= RACK_HAD_PUSH;
}
-
SOCK_SENDBUF_UNLOCK(so);
} else {
SOCK_SENDBUF_UNLOCK(so);
@@ -22536,7 +22552,7 @@ enobufs:
segsiz, pace_max_seg, hw_tls,
flags);
if (rack->r_fast_output) {
error = 0;
- ret = rack_fast_output(tp, rack, ts_val, cts,
ms_cts, &tv, tot_len_this_send, &error);
+ ret = rack_fast_output(tp, rack, ts_val, cts,
ms_cts, &tv, &tot_len_this_send, &error, __LINE__);
if (ret >= 0)
return (ret);
else if (error)
