tcp: extend F-RTO to catch more spurious timeouts

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Current F-RTO reverts cwnd reset whenever a never-retransmitted
packet was (s)acked. The timeout can be declared spurious because
the packets acknoledged with this ACK was transmitted before the
timeout, so clearly not all the packets are lost to reset the cwnd.

This nice detection does not really depend F-RTO internals. This
patch applies the detection universally. On Google servers this
change detected 20% more spurious timeouts.

Suggested-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

...

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Yuchung Cheng 2017-01-12 22:11:37 -08:00 • committed by David S. Miller

parent a0370b3f3f

commit 89fe18e44f

1 changed files with 19 additions and 14 deletions

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net/ipv4/tcp_input.c

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