svn commit: r242261 - head/sys/netinet

[Rui Paulo]

On Oct 28, 2012, at 14:56, Andre Oppermann <andre at freebsd.org> wrote:

> On 28.10.2012 22:34, Rui Paulo wrote:
>> On 28 Oct 2012, at 12:02, Andre Oppermann <andre at FreeBSD.org> wrote:
>> 
>>> Author: andre
>>> Date: Sun Oct 28 19:02:07 2012
>>> New Revision: 242261
>>> URL: http://svn.freebsd.org/changeset/base/242261
>>> 
>>> Log:
>>>  For retransmits of SYN|ACK from the syncache use the slightly more
>>>  aggressive special tcp_syn_backoff[] retransmit schedule instead of
>>>  the normal tcp_backoff[] schedule for established connections.
>> 
>> 
>> How did you came up with the values for tcp_syn_backoff? I obviously
> > understand the aggressiveness, but did you measure any significant
> > improvement in connection establishment time and if so, on what type of links?
> 
> I didn't come up with the values.  tcp_syn_backoff[] was introduced
> almost 12 years ago by jlemon.  For syncache it got lost somewhere
> along the line.

Oh, I see. I read it backwards. 

> 
> There has been recent talk by some large FreeBSD web server operators
> of reducing SYN|ACK retransmit timeouts.  This change fixes a part of
> the problem.  The recent RFC on reducing the RTO will fix the other
> part.

Which RFC? I'm only aware of draft-hurtig-tcpm-rtorestart.