tcp: use sequence distance to detect reordering

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Replace the reordering distance measurement in packet unit with
sequence based approach. Previously it trackes the number of "packets"
toward the forward ACK (i.e.  highest sacked sequence)in a state
variable "fackets_out".

Precisely measuring reordering degree on packet distance has not much
benefit, as the degree constantly changes by factors like path, load,
and congestion window. It is also complicated and prone to arcane bugs.
This patch replaces with sequence-based approach that's much simpler.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

...

This commit is contained in:

Yuchung Cheng 2017-11-08 13:01:27 -08:00 • committed by David S. Miller

parent 713bafea92

commit 737ff31456

5 changed files with 68 additions and 107 deletions

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1

include/linux/tcp.h

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1

net/ipv4/tcp.c

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155

net/ipv4/tcp_input.c

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1

net/ipv4/tcp_minisocks.c

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17

net/ipv4/tcp_output.c

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