Re: TCP Congestion Window Bug?

[David S. Miller]

Mark Reginald James writes:
 > TCP only sends a packet if:
 > 
 >          tcp_packets_in_flight(tp) < tp->snd_cwnd
 > 
 >          (function tcp_snd_test in include/net/tcp.h)
 > 
 > but regards transmission as application-limited if
 > 
 >          tp->packets_out < tp->snd_cwnd
 > 
 >          (function tcp_cwnd_validate in include/net/tcp.h)
 > 
 > So the kernel _always_ thinks the connection is
 > application-limited

Why?  After the final "send a packet if" test, tp->packets_out will be
incremented and thus be equal to tp->snd_cwnd, marking the connection
as _not_ application limited.

Later,
David S. Miller
[e-mail]