tcp: add a sysctl to config the tcp_default_init_rwnd
The default initial rwnd is hardcoded to 10.
Now we allow it to be controlled via
/proc/sys/net/ipv4/tcp_default_init_rwnd
which limits the values from 3 to 100
This is somewhat needed because ipv6 routes are
autoconfigured by the kernel.
See "An Argument for Increasing TCP's Initial Congestion Window"
in https://developers.google.com/speed/articles/tcp_initcwnd_paper.pdf
Change-Id: I386b2a9d62de0ebe05c1ebe1b4bd91b314af5c54
Signed-off-by: JP Abgrall <jpa@google.com>
Conflicts:
net/ipv4/sysctl_net_ipv4.c
net/ipv4/tcp_input.c
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index d4c5115..da34f83 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -102,6 +102,7 @@
int sysctl_tcp_moderate_rcvbuf __read_mostly = 1;
int sysctl_tcp_early_retrans __read_mostly = 3;
int sysctl_tcp_invalid_ratelimit __read_mostly = HZ/2;
+int sysctl_tcp_default_init_rwnd __read_mostly = TCP_INIT_CWND * 2;
#define FLAG_DATA 0x01 /* Incoming frame contained data. */
#define FLAG_WIN_UPDATE 0x02 /* Incoming ACK was a window update. */