tcp_cubic: make the delay threshold of HyStart less sensitive

Make HyStart less sensitive to abrupt delay variations due to buffer bloat.

Signed-off-by: Sangtae Ha <sangtae.ha@gmail.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Reported-by: Lucas Nussbaum <lucas.nussbaum@loria.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c
index 5e0491d..7172c12 100644 (file)
--- a/net/ipv4/tcp_cubic.c
+++ b/net/ipv4/tcp_cubic.c
@@ -39,7 +39,7 @@
 
 /* Number of delay samples for detecting the increase of delay */
 #define HYSTART_MIN_SAMPLES    8
-#define HYSTART_DELAY_MIN      (2U<<3)
+#define HYSTART_DELAY_MIN      (4U<<3)
 #define HYSTART_DELAY_MAX      (16U<<3)
 #define HYSTART_DELAY_THRESH(x)        clamp(x, HYSTART_DELAY_MIN, HYSTART_DELAY_MAX)