freebsd stable - Feb 2006 - tcp throughput and net.inet.tcp.inflight.enable

For a local server, is there any reason why I would want to keep 
net.inet.tcp.inflight.enable on ?  I was kind of surprised at the 
difference in the results with it on and off


[backup3]# iperf -c 10.1.1.2
------------------------------------------------------------
Client connecting to 10.1.1.2, TCP port 5001
TCP window size: 65.0 KByte (default)
------------------------------------------------------------
[  3] local 10.2.2.2 port 59056 connected with 10.1.1.2 port 5001
[  3]  0.0-10.0 sec    396 MBytes    333 Mbits/sec
[backup3]# sysctl -w net.inet.tcp.inflight.enable=0
net.inet.tcp.inflight.enable: 1 -> 0
[backup3]# iperf -c 10.1.1.2
------------------------------------------------------------
Client connecting to 10.1.1.2, TCP port 5001
TCP window size: 65.0 KByte (default)
------------------------------------------------------------
[  3] local 10.2.2.2 port 64685 connected with 10.1.1.2 port 5001
[  3]  0.0-10.0 sec    788 MBytes    661 Mbits/sec
[backup3]#


         ---Mike


--------------------------------------------------------------------
Mike Tancsa,                                      tel +1 519 651 3400
Sentex Communications,                            mike@sentex.net
Providing Internet since 1994                    www.sentex.net
Cambridge, Ontario Canada                         www.sentex.net/mike

On Wed, Feb 15, 2006 at 11:17:41PM -0500, Mike Tancsa
wrote:
> For a local server, is there any reason why I would want to keep 
> net.inet.tcp.inflight.enable on ?  I was kind of surprised at the 
> difference in the results with it on and off
I think in a situation where your network is fast and large amounts
of buffering do not imply high latency, then the inflight limiting
stuff probably isn't useful.

(I have some coworkers who reckon that inflight limiting can do the
wrong thing in other situations too, but they haven't had a chance
to investigate their suspicions yet.)

	David.