IPv6 window scaling factor always 1 on initial SYN

Bjoern A. Zeeb bz at FreeBSD.org
Mon Apr 6 10:24:13 PDT 2009

On Mon, 6 Apr 2009, sthaug at nethelp.no wrote:

>> Ok, both versions had:	< so->so_rcv.sb_hiwat)
>> http://svn.freebsd.org/viewvc/base?view=revision&revision=166403
>> changed it for IPv4 the first time,
>> http://svn.freebsd.org/viewvc/base?view=revision&revision=172795
>> changed it a second time for IPv4.
>> Noone changed the IPv6 version.
>> The syncache already seems to do it for both v4/v6 (common code).
>> Can you try changing it to < sb_max) for IPv6 as well and see if
>> things work (better) for you?
> I changed it, and that worked like a dream. Now I get basically the
> same throughput with IPv4 and IPv6.

That sounds great! :-)

>  There are of course still issues
> like lots of IPv6 tunnels that add extra latency - but that's not the
> fault of FreeBSD.

> Anyway, thanks for your work. Below is a context diff (against 7-STABLE
> cvsupped last night). Do we need a PR to get this into FreeBSD?

No, not even the context diff would have been needed;-)  I'll commit
it as soon as I find a few quiet minutes and a src tree;-)


Bjoern A. Zeeb                      The greatest risk is not taking one.

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