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tcp: LRO timestamps have lost their previous precision

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Recently we had a rewrite to tcp_lro.c that was tested but one subtle change
was the move to a less precise timestamp. This causes all kinds of chaos
in tcp's that do pacing and needs to be fixed to use the more precise
time that was there before.

Reviewed by: mtuexen, gallatin, hselasky
Sponsored by: Netflix Inc
Differential Revision:	https://reviews.freebsd.org/D30695
This commit is contained in:
Randall Stewart 2021-06-09 13:58:54 -04:00
parent 5e5ca4c8fc
commit b45daaea95
3 changed files with 26 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
sys/netinet/tcp_lro.c
View File

@ -562,16 +562,18 @@ void
tcp_lro_flush_inactive(struct lro_ctrl *lc, const struct timeval *timeout)
{
struct lro_entry *le, *le_tmp;
sbintime_t sbt;
uint64_t now, tov;
struct bintime bt;
if (LIST_EMPTY(&lc->lro_active))
return;
/* get timeout time */
sbt = getsbinuptime() - tvtosbt(*timeout);
/* get timeout time and current time in ns */
binuptime(&bt);
now = bintime2ns(&bt);
tov = ((timeout->tv_sec * 1000000000) + (timeout->tv_usec * 1000));
LIST_FOREACH_SAFE(le, &lc->lro_active, next, le_tmp) {
if (sbt >= le->alloc_time) {
if (now >= (bintime2ns(&le->alloc_time) + tov)) {
tcp_lro_active_remove(le);
tcp_lro_flush(lc, le);
}
@ -610,7 +612,7 @@ tcp_lro_log(struct tcpcb *tp, const struct lro_ctrl *lc,
{
if (tp->t_logstate != TCP_LOG_STATE_OFF) {
union tcp_log_stackspecific log;
struct timeval tv;
struct timeval tv, btv;
uint32_t cts;
cts = tcp_get_usecs(&tv);
@ -637,7 +639,8 @@ tcp_lro_log(struct tcpcb *tp, const struct lro_ctrl *lc,
log.u_bbr.cwnd_gain = le->window;
log.u_bbr.cur_del_rate = (uintptr_t)m;
log.u_bbr.bw_inuse = (uintptr_t)le->m_head;
log.u_bbr.flex6 = sbttous(lc->lro_last_queue_time);
bintime2timeval(&lc->lro_last_queue_time, &btv);
log.u_bbr.flex6 = tcp_tv_to_usectick(&btv);
log.u_bbr.flex7 = le->compressed;
log.u_bbr.pacing_gain = le->uncompressed;
if (in_epoch(net_epoch_preempt))
@ -1446,7 +1449,7 @@ tcp_lro_flush_all(struct lro_ctrl *lc)
CURVNET_SET(lc->ifp->if_vnet);
/* get current time */
lc->lro_last_queue_time = getsbinuptime();
binuptime(&lc->lro_last_queue_time);
/* sort all mbufs according to stream */
tcp_lro_sort(lc->lro_mbuf_data, lc->lro_mbuf_count);
@ -1739,7 +1742,7 @@ tcp_lro_rx_common(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum, bool use_h
#endif
/* If no hardware or arrival stamp on the packet add timestamp */
if ((m->m_flags & (M_TSTMP_LRO | M_TSTMP)) == 0) {
m->m_pkthdr.rcv_tstmp = sbttons(lc->lro_last_queue_time);
m->m_pkthdr.rcv_tstmp = bintime2ns(&lc->lro_last_queue_time);
m->m_flags |= M_TSTMP_LRO;
}
@ -1834,7 +1837,7 @@ tcp_lro_rx(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum)
int error;
/* get current time */
lc->lro_last_queue_time = getsbinuptime();
binuptime(&lc->lro_last_queue_time);
CURVNET_SET(lc->ifp->if_vnet);
error = tcp_lro_rx_common(lc, m, csum, true);

4
sys/netinet/tcp_lro.h
View File

@ -140,7 +140,7 @@ struct lro_entry {
uint16_t uncompressed;
uint16_t window;
uint16_t timestamp; /* flag, not a TCP hdr field. */
sbintime_t alloc_time; /* time when entry was allocated */
struct bintime alloc_time; /* time when entry was allocated */
};
LIST_HEAD(lro_head, lro_entry);
@ -154,7 +154,7 @@ struct lro_mbuf_sort {
struct lro_ctrl {
struct ifnet *ifp;
struct lro_mbuf_sort *lro_mbuf_data;
sbintime_t lro_last_queue_time; /* last time data was queued */
struct bintime lro_last_queue_time; /* last time data was queued */
uint64_t lro_queued;
uint64_t lro_flushed;
uint64_t lro_bad_csum;

11
sys/sys/time.h
View File

@ -286,6 +286,17 @@ bintime2timespec(const struct bintime *_bt, struct timespec *_ts)
(uint32_t)(_bt->frac >> 32)) >> 32;
}
static __inline uint64_t
bintime2ns(const struct bintime *_bt)
{
uint64_t ret;
ret = (uint64_t)(_bt->sec) * (uint64_t)1000000000;
ret += (((uint64_t)1000000000 *
(uint32_t)(_bt->frac >> 32)) >> 32);
return (ret);
}
static __inline void
timespec2bintime(const struct timespec *_ts, struct bintime *_bt)
{