Dave, this is the 2.4 version of Stephen's patch which removes bw_sample. I did even few small changes to comments which were simply too old and didn't reflect in any way the current implementation. It applies against 2.4.26-pre3. Regards. -- Angelo Dell'Aera 'buffer' Antifork Research, Inc. http://buffer.antifork.org diff -Naur linux-2.4.26-pre3-old/include/net/sock.h linux-2.4.26-pre3/include/net/sock.h --- linux-2.4.26-pre3-old/include/net/sock.h 2004-03-15 16:23:02.000000000 +0100 +++ linux-2.4.26-pre3/include/net/sock.h 2004-03-15 16:26:30.000000000 +0100 @@ -435,7 +435,6 @@ /* TCP Westwood structure */ struct { - __u32 bw_sample; /* bandwidth sample */ __u32 bw_ns_est; /* first bandwidth estimation..not too smoothed 8) */ __u32 bw_est; /* bandwidth estimate */ __u32 rtt_win_sx; /* here starts a new evaluation... */ diff -Naur linux-2.4.26-pre3-old/include/net/tcp.h linux-2.4.26-pre3/include/net/tcp.h --- linux-2.4.26-pre3-old/include/net/tcp.h 2004-03-15 16:23:02.000000000 +0100 +++ linux-2.4.26-pre3/include/net/tcp.h 2004-03-15 16:32:28.000000000 +0100 @@ -1880,16 +1880,18 @@ void __tcp_westwood_slow_bw(struct sock *, struct sk_buff *); /* - * This function initializes fields used in TCP Westwood. - * We can't get no information about RTT at this time so - * we are forced to set it to 0. + * This function initializes fields used in TCP Westwood+. We can't + * get no information about RTTmin at this time so we simply set it to + * TCP_WESTWOOD_INIT_RTT. This value was chosen to be too conservative + * since in this way we're sure it will be updated in a consistent + * way as soon as possible. It will reasonably happen within the first + * RTT period of the connection lifetime. */ static inline void __tcp_init_westwood(struct sock *sk) { struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp); - tp->westwood.bw_sample = 0; tp->westwood.bw_ns_est = 0; tp->westwood.bw_est = 0; tp->westwood.accounted = 0; diff -Naur linux-2.4.26-pre3-old/net/ipv4/tcp_input.c linux-2.4.26-pre3/net/ipv4/tcp_input.c --- linux-2.4.26-pre3-old/net/ipv4/tcp_input.c 2004-03-15 16:23:05.000000000 +0100 +++ linux-2.4.26-pre3/net/ipv4/tcp_input.c 2004-03-15 16:30:28.000000000 +0100 @@ -2038,8 +2038,7 @@ } /* - * TCP Westwood - * Functions needed for estimating bandwidth. + * TCP Westwood+ */ /* @@ -2055,14 +2054,13 @@ static void westwood_filter(struct sock *sk, __u32 delta) { struct tcp_opt *tp = &(sk->tp_pinfo.af_tcp); - __u32 sample = (tp->westwood.bk) / delta; tp->westwood.bw_ns_est = - westwood_do_filter(tp->westwood.bw_ns_est, sample); + westwood_do_filter(tp->westwood.bw_ns_est, + tp->westwood.bk / delta); tp->westwood.bw_est = westwood_do_filter(tp->westwood.bw_est, tp->westwood.bw_ns_est); - tp->westwood.bw_sample = sample; } /* @westwood_update_rttmin @@ -2086,8 +2084,7 @@ /* * @westwood_acked - * Evaluate increases for dk. It requires no lock since when it is - * called lock should already be held. Be careful about it! + * Evaluate increases for dk. */ static __u32 westwood_acked(struct sock *sk) @@ -2134,10 +2131,7 @@ /* * @westwood_update_window * It updates RTT evaluation window if it is the right moment to do - * it. If so it calls filter for evaluating bandwidth. Be careful - * about __westwood_update_window() since it is called without - * any form of lock. It should be used only for internal purposes. - * Call westwood_update_window() instead. + * it. If so it calls filter for evaluating bandwidth. */ static void __westwood_update_window(struct sock *sk, __u32 now) @@ -2162,7 +2156,7 @@ } /* - * @__westwood_fast_bw + * @__tcp_westwood_fast_bw * It is called when we are in fast path. In particular it is called when * header prediction is successfull. In such case infact update is * straight forward and doesn't need any particular care. @@ -2253,7 +2247,7 @@ } /* - * @__westwood_slow_bw + * @__tcp_westwood_slow_bw * It is called when something is going wrong..even if there could * be no problems! Infact a simple delayed packet may trigger a * dupack. But we need to be careful in such case. @@ -2269,7 +2263,7 @@ tp->westwood.rtt_min = westwood_update_rttmin(sk); } -/* TCP Westwood routines end here */ +/* TCP Westwood+ routines end here */ /* This routine deals with incoming acks, but not outgoing ones. */ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag) - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
