From 7e38017557bc0b87434d184f8804cadb102bb903 Mon Sep 17 00:00:00 2001 From: Andreas Petlund Date: Thu, 18 Feb 2010 04:48:19 +0000 Subject: net: TCP thin dupack This patch enables fast retransmissions after one dupACK for TCP if the stream is identified as thin. This will reduce latencies for thin streams that are not able to trigger fast retransmissions due to high packet interarrival time. This mechanism is only active if enabled by iocontrol or syscontrol and the stream is identified as thin. Signed-off-by: Andreas Petlund Signed-off-by: David S. Miller --- include/linux/tcp.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'include/linux/tcp.h') diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 3ba8b074612f..a778ee024590 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -104,6 +104,7 @@ enum { #define TCP_MD5SIG 14 /* TCP MD5 Signature (RFC2385) */ #define TCP_COOKIE_TRANSACTIONS 15 /* TCP Cookie Transactions */ #define TCP_THIN_LINEAR_TIMEOUTS 16 /* Use linear timeouts for thin streams*/ +#define TCP_THIN_DUPACK 17 /* Fast retrans. after 1 dupack */ /* for TCP_INFO socket option */ #define TCPI_OPT_TIMESTAMPS 1 @@ -343,7 +344,8 @@ struct tcp_sock { u8 frto_counter; /* Number of new acks after RTO */ u8 nonagle : 4,/* Disable Nagle algorithm? */ thin_lto : 1,/* Use linear timeouts for thin streams */ - unused : 3; + thin_dupack : 1,/* Fast retransmit on first dupack */ + unused : 2; /* RTT measurement */ u32 srtt; /* smoothed round trip time << 3 */ -- cgit v1.2.3