diff options
Diffstat (limited to 'net/ipv4/tcp_cubic.c')
| -rw-r--r-- | net/ipv4/tcp_cubic.c | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c index 068775b91fb5..0e5428ed04fe 100644 --- a/net/ipv4/tcp_cubic.c +++ b/net/ipv4/tcp_cubic.c @@ -436,8 +436,27 @@ static void bictcp_acked(struct sock *sk, const struct ack_sample *sample) delay = 1; /* first time call or link delay decreases */ - if (ca->delay_min == 0 || ca->delay_min > delay) - ca->delay_min = delay; + if (ca->delay_min == 0 || ca->delay_min > delay) { + unsigned long rate = READ_ONCE(sk->sk_pacing_rate); + + /* Account for TSO/GRO delays. + * Otherwise short RTT flows could get too small ssthresh, + * since during slow start we begin with small TSO packets + * and could lower ca->delay_min too much. + * Ideally even with a very small RTT we would like to have + * at least one TSO packet being sent and received by GRO, + * and another one in qdisc layer. + * We apply another 100% factor because @rate is doubled at + * this point. + * We cap the cushion to 1ms. + */ + if (rate) + delay += min_t(u64, USEC_PER_MSEC, + div64_ul((u64)GSO_MAX_SIZE * + 4 * USEC_PER_SEC, rate)); + if (ca->delay_min == 0 || ca->delay_min > delay) + ca->delay_min = delay; + } /* hystart triggers when cwnd is larger than some threshold */ if (!ca->found && hystart && tcp_in_slow_start(tp) && |