* Re: TCP Congestion Window Bug?
2001-03-04 5:39 TCP Congestion Window Bug? Mark Reginald James
@ 2001-03-03 9:11 ` David S. Miller
2001-03-04 6:28 ` Mark Reginald James
1 sibling, 0 replies; 3+ messages in thread
From: David S. Miller @ 2001-03-03 9:11 UTC (permalink / raw)
To: Mark Reginald James; +Cc: linux-kernel
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
davem@redhat.com
^ permalink raw reply [flat|nested] 3+ messages in thread
* TCP Congestion Window Bug?
@ 2001-03-04 5:39 Mark Reginald James
2001-03-03 9:11 ` David S. Miller
2001-03-04 6:28 ` Mark Reginald James
0 siblings, 2 replies; 3+ messages in thread
From: Mark Reginald James @ 2001-03-04 5:39 UTC (permalink / raw)
To: linux-kernel
Hi:
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, forcing many un-necessary
reductions in the size of the congestion window.
I think the condition in tcp_snd_test should be:
tcp_packets_in_flight(tp) <= tp->snd_cwnd
Mark
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: TCP Congestion Window Bug?
2001-03-04 5:39 TCP Congestion Window Bug? Mark Reginald James
2001-03-03 9:11 ` David S. Miller
@ 2001-03-04 6:28 ` Mark Reginald James
1 sibling, 0 replies; 3+ messages in thread
From: Mark Reginald James @ 2001-03-04 6:28 UTC (permalink / raw)
To: linux-kernel
Please ignore original post. Sorry. -- Mark
^ permalink raw reply [flat|nested] 3+ messages in thread
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2001-03-04 5:39 TCP Congestion Window Bug? Mark Reginald James
2001-03-03 9:11 ` David S. Miller
2001-03-04 6:28 ` Mark Reginald James
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