tcp_cubic: make ack train delta value a parameter
Make the spacing between ACK's that indicates a train a tuneable
value like other hystart values.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c
index 43bb34c..66d3b00 100644
--- a/net/ipv4/tcp_cubic.c
+++ b/net/ipv4/tcp_cubic.c
@@ -52,6 +52,7 @@
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 @@
" 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 @@
/* 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)