TCP拥塞控制算法 — CUBIC的补丁（二）
描述
以下是提交者Stephen Hemminger对这个patch的描述：
make ack train delta value a parameter
Make the spacing between ACK's that indicates a train a tuneable value like other bystart values.
代码
--- a/net/ipv4/tcp_cubic.c+++ b/net/ipv4/tcp_cubic.c@@ -52,6 +52,7 @@ static int tcp_friendliness __read_mostly = 1; static int hystart __read_mostly = 1; static int hystart_detect __read_mostly = HYSTART_ACK_TRAIN | HYSTART_DELAY; static int hystart_low_window __read_mostly = 16;+static int hystart_ack_delta __read_mostly = 2; static u32 cube_rtt_scale __read_mostly; static u32 beta_scale __read_mostly;@@ -75,6 +76,8 @@ MODULE_PARM_DESC(hystart_detect, "hyrbrid slow start detection mechanisms" " 1: packet-train 2: delay 3: both packet-train and delay"); module_param(hystart_low_window, int, 0644); MODULE_PARM_DESC(hystart_low_window, "lower bound cwnd for hybrid slow start");+module_param(hystart_ack_delta, int, 0644);+MODULE_PARM_DESC(hystart_ack_delta, "spacing between ack's indicating train (msecs)"); /* BIC TCP Parameters */ struct bictcp {@@ -343,7 +346,7 @@ static void hystart_update(struct sock *sk, u32 delay) /* first detection parameter - ack-train detection */ if ((s32)(curr_jiffies - ca->last_jiffies) <=- msecs_to_jiffies(2)) {+ msecs_to_jiffies(hystart_ack_delta)) { ca->last_jiffies = curr_jiffies; if ((s32) (curr_jiffies - ca->round_start) > ca->delay_min >> 4)评价
把ACK序列号之间允许的时间间隔设置为一个可调参数，允许用户自行调整。这个补丁并不是必须的。
Author
zhangskd @ csdn blog