This patch changes the API for the callback that is done after an ACK is received. It solves a couple of issues: * Some congestion controls want higher resolution value of RTT (controlled by TCP_CONG_RTT_SAMPLE flag). These don't really want a ktime, but all compute a RTT in microseconds. * Other congestion control methods could use RTT at jiffies resolution. To keep API consistent the units should be the same for both cases, just the resolution should change. A value -1 is used to indicate no valid timestamp is available. Signed-off-by: Stephen Hemminger --- a/include/net/tcp.h 2007-07-23 10:29:42.000000000 +0100 +++ b/include/net/tcp.h 2007-07-23 10:33:50.000000000 +0100 @@ -660,7 +660,7 @@ struct tcp_congestion_ops { /* new value of cwnd after loss (optional) */ u32 (*undo_cwnd)(struct sock *sk); /* hook for packet ack accounting (optional) */ - void (*pkts_acked)(struct sock *sk, u32 num_acked, ktime_t last); + void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us); /* get info for inet_diag (optional) */ void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb); --- a/net/ipv4/tcp_input.c 2007-07-23 10:29:42.000000000 +0100 +++ b/net/ipv4/tcp_input.c 2007-07-23 10:33:50.000000000 +0100 @@ -2490,12 +2490,23 @@ static int tcp_clean_rtx_queue(struct so tcp_ack_update_rtt(sk, acked, seq_rtt); tcp_ack_packets_out(sk); - /* Is the ACK triggering packet unambiguous? */ - if (acked & FLAG_RETRANS_DATA_ACKED) - last_ackt = net_invalid_timestamp(); + if (ca_ops->pkts_acked) { + s32 rtt_us = -1; - if (ca_ops->pkts_acked) - ca_ops->pkts_acked(sk, pkts_acked, last_ackt); + /* Is the ACK triggering packet unambiguous? */ + if (!(acked & FLAG_RETRANS_DATA_ACKED)) { + /* High resolution needed and available? */ + if (ca_ops->flags & TCP_CONG_RTT_STAMP && + !ktime_equal(last_ackt, + net_invalid_timestamp())) + rtt_us = ktime_us_delta(ktime_get_real(), + last_ackt); + else if (seq_rtt > 0) + rtt_us = jiffies_to_usecs(seq_rtt); + } + + ca_ops->pkts_acked(sk, pkts_acked, rtt_us); + } } #if FASTRETRANS_DEBUG > 0 --- a/net/ipv4/tcp_bic.c 2007-07-23 10:29:42.000000000 +0100 +++ b/net/ipv4/tcp_bic.c 2007-07-23 10:33:50.000000000 +0100 @@ -206,7 +206,7 @@ static void bictcp_state(struct sock *sk /* Track delayed acknowledgment ratio using sliding window * ratio = (15*ratio + sample) / 16 */ -static void bictcp_acked(struct sock *sk, u32 cnt, ktime_t last) +static void bictcp_acked(struct sock *sk, u32 cnt, s32 rtt) { const struct inet_connection_sock *icsk = inet_csk(sk); --- a/net/ipv4/tcp_cubic.c 2007-07-23 10:29:42.000000000 +0100 +++ b/net/ipv4/tcp_cubic.c 2007-07-23 10:33:50.000000000 +0100 @@ -334,7 +334,7 @@ static void bictcp_state(struct sock *sk /* Track delayed acknowledgment ratio using sliding window * ratio = (15*ratio + sample) / 16 */ -static void bictcp_acked(struct sock *sk, u32 cnt, ktime_t last) +static void bictcp_acked(struct sock *sk, u32 cnt, s32 rtt_us) { const struct inet_connection_sock *icsk = inet_csk(sk); --- a/net/ipv4/tcp_htcp.c 2007-07-23 10:29:42.000000000 +0100 +++ b/net/ipv4/tcp_htcp.c 2007-07-23 10:33:50.000000000 +0100 @@ -98,7 +98,7 @@ static inline void measure_rtt(struct so } } -static void measure_achieved_throughput(struct sock *sk, u32 pkts_acked, ktime_t last) +static void measure_achieved_throughput(struct sock *sk, u32 pkts_acked, s32 rtt) { const struct inet_connection_sock *icsk = inet_csk(sk); const struct tcp_sock *tp = tcp_sk(sk); --- a/net/ipv4/tcp_illinois.c 2007-07-23 10:29:42.000000000 +0100 +++ b/net/ipv4/tcp_illinois.c 2007-07-23 10:33:50.000000000 +0100 @@ -83,18 +83,16 @@ static void tcp_illinois_init(struct soc } /* Measure RTT for each ack. */ -static void tcp_illinois_acked(struct sock *sk, u32 pkts_acked, ktime_t last) +static void tcp_illinois_acked(struct sock *sk, u32 pkts_acked, s32 rtt) { struct illinois *ca = inet_csk_ca(sk); - u32 rtt; ca->acked = pkts_acked; - if (ktime_equal(last, net_invalid_timestamp())) + /* dup ack, no rtt sample */ + if (rtt < 0) return; - rtt = ktime_to_us(net_timedelta(last)); - /* ignore bogus values, this prevents wraparound in alpha math */ if (rtt > RTT_MAX) rtt = RTT_MAX; --- a/net/ipv4/tcp_lp.c 2007-07-23 10:29:42.000000000 +0100 +++ b/net/ipv4/tcp_lp.c 2007-07-23 10:33:50.000000000 +0100 @@ -260,13 +260,13 @@ static void tcp_lp_rtt_sample(struct soc * newReno in increase case. * We work it out by following the idea from TCP-LP's paper directly */ -static void tcp_lp_pkts_acked(struct sock *sk, u32 num_acked, ktime_t last) +static void tcp_lp_pkts_acked(struct sock *sk, u32 num_acked, s32 rtt_us) { struct tcp_sock *tp = tcp_sk(sk); struct lp *lp = inet_csk_ca(sk); - if (!ktime_equal(last, net_invalid_timestamp())) - tcp_lp_rtt_sample(sk, ktime_to_us(net_timedelta(last))); + if (rtt_us > 0) + tcp_lp_rtt_sample(sk, rtt_us); /* calc inference */ if (tcp_time_stamp > tp->rx_opt.rcv_tsecr) --- a/net/ipv4/tcp_vegas.c 2007-07-23 10:29:42.000000000 +0100 +++ b/net/ipv4/tcp_vegas.c 2007-07-23 10:33:50.000000000 +0100 @@ -112,16 +112,16 @@ EXPORT_SYMBOL_GPL(tcp_vegas_init); * o min-filter RTT samples from a much longer window (forever for now) * to find the propagation delay (baseRTT) */ -void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, ktime_t last) +void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, s32 rtt_us) { struct vegas *vegas = inet_csk_ca(sk); u32 vrtt; - if (ktime_equal(last, net_invalid_timestamp())) + if (rtt_us < 0) return; /* Never allow zero rtt or baseRTT */ - vrtt = ktime_to_us(net_timedelta(last)) + 1; + vrtt = rtt_us + 1; /* Filter to find propagation delay: */ if (vrtt < vegas->baseRTT) --- a/net/ipv4/tcp_vegas.h 2007-07-23 10:27:43.000000000 +0100 +++ b/net/ipv4/tcp_vegas.h 2007-07-23 10:33:50.000000000 +0100 @@ -17,7 +17,7 @@ struct vegas { extern void tcp_vegas_init(struct sock *sk); extern void tcp_vegas_state(struct sock *sk, u8 ca_state); -extern void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, ktime_t last); +extern void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, s32 rtt_us); extern void tcp_vegas_cwnd_event(struct sock *sk, enum tcp_ca_event event); extern void tcp_vegas_get_info(struct sock *sk, u32 ext, struct sk_buff *skb); --- a/net/ipv4/tcp_veno.c 2007-07-23 10:29:42.000000000 +0100 +++ b/net/ipv4/tcp_veno.c 2007-07-23 10:33:50.000000000 +0100 @@ -69,16 +69,16 @@ static void tcp_veno_init(struct sock *s } /* Do rtt sampling needed for Veno. */ -static void tcp_veno_pkts_acked(struct sock *sk, u32 cnt, ktime_t last) +static void tcp_veno_pkts_acked(struct sock *sk, u32 cnt, s32 rtt_us) { struct veno *veno = inet_csk_ca(sk); u32 vrtt; - if (ktime_equal(last, net_invalid_timestamp())) + if (rtt_us < 0) return; /* Never allow zero rtt or baseRTT */ - vrtt = ktime_to_us(net_timedelta(last)) + 1; + vrtt = rtt_us + 1; /* Filter to find propagation delay: */ if (vrtt < veno->basertt) --- a/net/ipv4/tcp_westwood.c 2007-07-23 10:27:43.000000000 +0100 +++ b/net/ipv4/tcp_westwood.c 2007-07-23 10:33:50.000000000 +0100 @@ -100,11 +100,12 @@ static void westwood_filter(struct westw * Called after processing group of packets. * but all westwood needs is the last sample of srtt. */ -static void tcp_westwood_pkts_acked(struct sock *sk, u32 cnt, ktime_t last) +static void tcp_westwood_pkts_acked(struct sock *sk, u32 cnt, s32 rtt) { struct westwood *w = inet_csk_ca(sk); - if (cnt > 0) - w->rtt = tcp_sk(sk)->srtt >> 3; + + if (rtt > 0) + w->rtt = usecs_to_jiffies(rtt); } /* --- a/net/ipv4/tcp_yeah.c 2007-07-23 10:29:42.000000000 +0100 +++ b/net/ipv4/tcp_yeah.c 2007-07-23 10:33:50.000000000 +0100 @@ -58,7 +58,7 @@ static void tcp_yeah_init(struct sock *s } -static void tcp_yeah_pkts_acked(struct sock *sk, u32 pkts_acked, ktime_t last) +static void tcp_yeah_pkts_acked(struct sock *sk, u32 pkts_acked, s32 rtt_us) { const struct inet_connection_sock *icsk = inet_csk(sk); struct yeah *yeah = inet_csk_ca(sk); @@ -66,7 +66,7 @@ static void tcp_yeah_pkts_acked(struct s if (icsk->icsk_ca_state == TCP_CA_Open) yeah->pkts_acked = pkts_acked; - tcp_vegas_pkts_acked(sk, pkts_acked, last); + tcp_vegas_pkts_acked(sk, pkts_acked, rtt_us); } static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack, -- - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html