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| author | Stephen Hemminger <shemminger@linux-foundation.org> | 2007-08-07 18:29:05 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2007-08-07 18:29:05 -0700 |
| commit | f34d1955dff5a5769d24614d137003f0316406f3 (patch) | |
| tree | 4787a616396aa8ea32bdb262043e7b784861cbeb /net | |
| parent | 591e620693e71e24fb3450a4084217e44b7a60b6 (diff) | |
| download | linux-f34d1955dff5a5769d24614d137003f0316406f3.tar.gz linux-f34d1955dff5a5769d24614d137003f0316406f3.tar.bz2 linux-f34d1955dff5a5769d24614d137003f0316406f3.zip | |
[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) static inline void measure_rtt(struct sock *sk, u32 srtt) { const struct inet_connection_sock *icsk = inet_csk(sk); - const struct tcp_sock *tp = tcp_sk(sk); struct htcp *ca = inet_csk_ca(sk); /* 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) ca->minRTT = srtt; /* max RTT */ - if (icsk->icsk_ca_state == TCP_CA_Open - && tp->snd_ssthresh < 0xFFFF && htcp_ccount(ca) > 3) { + if (icsk->icsk_ca_state == TCP_CA_Open) { if (ca->maxRTT < ca->minRTT) ca->maxRTT = ca->minRTT; if (ca->maxRTT < srtt |