DragonFly BSD
DragonFly kernel List (threaded) for 2005-07
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Re: MAXSAVEDBLOCKS in netinet/tcp_sack.c

From: Noritoshi Demizu <demizu@xxxxxxxxxxxxxx>
Date: Tue, 05 Jul 2005 18:55:27 +0900 (JST)

>     In anycase, RED or fair-queueing tend to do a much better job 
>     reducing the number of fragmented ranges.  SACK running through a
>     RED router (which is most of the routers on the internet) is a good
>     combination.

Thanks.  If my purpose is to transfer data as fast as possible,
it would be a good solution.  But what I want to do now is to observe
TCP behaviors in the slow start phase after retransmission timeouts.
So, I think my environment is quite good :-) for me.

>     If you have a lot of outgoing bandwidth and the servers are running
>     FreeBSD or DragonFly, you can turn on the inflight bandwidth limiting
>     sysctl (net.inet.tcp.inflight_enable).  This only works on the machines
>     doing the actual initiation of the packets, it won't work on the 
>     routers.  It does a fairly good job reducing queue lengths.

Sorry, actually, I always set net.inet.tcp.inflight_enable to zero
both on DragonFlyBSD and FreeBSD in my experiences (I know it is zero
on DragonFlyBSD by default, but I want to make it sure), because
unfortunately it reduces throughput in my experiences in an unexpected

Noritoshi Demizu

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