netdev - Re: 3 packet TCP window limit?

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Date:	Wed, 5 May 2010 13:01:19 -0700 (PDT)
From:	dormando <dormando@...ia.net>
To:	Brian Bloniarz <bmb@...enacr.com>
cc:	netdev@...r.kernel.org
Subject: Re: 3 packet TCP window limit?

> This sounds like TCP slow start.
>
> http://en.wikipedia.org/wiki/Slow-start
>
> As far as tunables you might want to play with the initcwnd route
> flag (see "ip route help")

Ah, yes, initcwnd was it. I'm well aware of TCP Congestion control / slow
start / etc. However I couldn't find the damn tunable for it :)
ssthresh/tso/etc didn't seem to unwedge it. Felt like describing it in the
most generic way possible would help :)

Other OS's appear to have a larger initcwnd. As do commercial load
balancers. The default of 3 seems to be tuned for 56k dialup modems. I'm a
little surprised that none of the pluggable TCP congestion control
algorithms changed this value. I went through all of them except for
tcp_yeah.

Anyway, thanks and sorry for the nearly off-topic post here. I see some
google papers on bumping initcwnd to 10... but I guess that's not linux's
deal yet.
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