diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/vnet/tcp/tcp_cubic.c | 34 |
1 files changed, 25 insertions, 9 deletions
diff --git a/src/vnet/tcp/tcp_cubic.c b/src/vnet/tcp/tcp_cubic.c index 55bbcca3497..717c54b146a 100644 --- a/src/vnet/tcp/tcp_cubic.c +++ b/src/vnet/tcp/tcp_cubic.c @@ -69,10 +69,12 @@ W_cubic (cubic_data_t * cd, f64 t) * RFC 8312 Eq. 2 */ static inline f64 -K_cubic (cubic_data_t * cd) +K_cubic (cubic_data_t * cd, u32 wnd) { - /* K = cubic_root(W_max*(1-beta_cubic)/C) */ - return pow (cd->w_max * (1 - beta_cubic) / cubic_c, 1 / 3.0); + /* K = cubic_root(W_max*(1-beta_cubic)/C) + * Because the current window may be less than W_max * beta_cubic because + * of fast convergence, we pass it as parameter */ + return pow ((f64) (cd->w_max - wnd) / cubic_c, 1 / 3.0); } /** @@ -108,8 +110,23 @@ cubic_recovered (tcp_connection_t * tc) { cubic_data_t *cd = (cubic_data_t *) tcp_cc_data (tc); cd->t_start = cubic_time (tc->c_thread_index); - cd->K = K_cubic (cd); tc->cwnd = tc->ssthresh; + cd->K = K_cubic (cd, tc->cwnd / tc->snd_mss); +} + +static void +cubic_cwnd_accumulate (tcp_connection_t * tc, u32 thresh, u32 bytes_acked) +{ + /* We just updated the threshold and don't know how large the previous + * one was. Still, optimistically increase cwnd by one segment and + * clear the accumulated bytes. */ + if (tc->cwnd_acc_bytes > thresh) + { + tc->cwnd += tc->snd_mss; + tc->cwnd_acc_bytes = 0; + } + + tcp_cwnd_accumulate (tc, thresh, tc->bytes_acked); } static void @@ -137,7 +154,7 @@ cubic_rcv_ack (tcp_connection_t * tc) w_aimd = (u64) W_est (cd, t, rtt_sec) * tc->snd_mss; if (w_cubic < w_aimd) { - tcp_cwnd_accumulate (tc, tc->cwnd, tc->bytes_acked); + cubic_cwnd_accumulate (tc, tc->cwnd, tc->bytes_acked); } else { @@ -155,16 +172,15 @@ cubic_rcv_ack (tcp_connection_t * tc) */ thresh = (tc->snd_mss * tc->cwnd) / (w_cubic - tc->cwnd); - /* Make sure we don't increase cwnd more often than every - * 2 segments */ - thresh = clib_max (thresh, 2 * tc->snd_mss); + /* Make sure we don't increase cwnd more often than every segment */ + thresh = clib_max (thresh, tc->snd_mss); } else { /* Practically we can't increment so just inflate threshold */ thresh = 50 * tc->cwnd; } - tcp_cwnd_accumulate (tc, thresh, tc->bytes_acked); + cubic_cwnd_accumulate (tc, thresh, tc->bytes_acked); } } |