diff options
author | Stephen Hemminger <shemminger@linux-foundation.org> | 2007-08-07 21:29:05 -0400 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2007-08-07 21:29:05 -0400 |
commit | f34d1955dff5a5769d24614d137003f0316406f3 (patch) | |
tree | 4787a616396aa8ea32bdb262043e7b784861cbeb /net | |
parent | 591e620693e71e24fb3450a4084217e44b7a60b6 (diff) |
[TCP]: H-TCP maxRTT estimation at startup
Small patch to H-TCP from Douglas Leith.
Fix estimation of maxRTT. The original code ignores rtt measurements
during slow start (via the check tp->snd_ssthresh < 0xFFFF) yet this
is probably a good time to try to estimate max rtt as delayed acking
is disabled and slow start will only exit on a loss which presumably
corresponds to a maxrtt measurement. Second, the original code (via
the check htcp_ccount(ca) > 3) ignores rtt data during what it
estimates to be the first 3 round-trip times. This seems like an
unnecessary check now that the RCV timestamp are no longer used
for rtt estimation.
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r-- | net/ipv4/tcp_htcp.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/net/ipv4/tcp_htcp.c b/net/ipv4/tcp_htcp.c index b66556c0a5bd..5215691f2760 100644 --- a/net/ipv4/tcp_htcp.c +++ b/net/ipv4/tcp_htcp.c | |||
@@ -79,7 +79,6 @@ static u32 htcp_cwnd_undo(struct sock *sk) | |||
79 | static inline void measure_rtt(struct sock *sk, u32 srtt) | 79 | static inline void measure_rtt(struct sock *sk, u32 srtt) |
80 | { | 80 | { |
81 | const struct inet_connection_sock *icsk = inet_csk(sk); | 81 | const struct inet_connection_sock *icsk = inet_csk(sk); |
82 | const struct tcp_sock *tp = tcp_sk(sk); | ||
83 | struct htcp *ca = inet_csk_ca(sk); | 82 | struct htcp *ca = inet_csk_ca(sk); |
84 | 83 | ||
85 | /* keep track of minimum RTT seen so far, minRTT is zero at first */ | 84 | /* keep track of minimum RTT seen so far, minRTT is zero at first */ |
@@ -87,8 +86,7 @@ static inline void measure_rtt(struct sock *sk, u32 srtt) | |||
87 | ca->minRTT = srtt; | 86 | ca->minRTT = srtt; |
88 | 87 | ||
89 | /* max RTT */ | 88 | /* max RTT */ |
90 | if (icsk->icsk_ca_state == TCP_CA_Open | 89 | if (icsk->icsk_ca_state == TCP_CA_Open) { |
91 | && tp->snd_ssthresh < 0xFFFF && htcp_ccount(ca) > 3) { | ||
92 | if (ca->maxRTT < ca->minRTT) | 90 | if (ca->maxRTT < ca->minRTT) |
93 | ca->maxRTT = ca->minRTT; | 91 | ca->maxRTT = ca->minRTT; |
94 | if (ca->maxRTT < srtt | 92 | if (ca->maxRTT < srtt |