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Date:      Sun, 28 Oct 2012 15:01:24 -0700
From:      Rui Paulo <rpaulo@felyko.com>
To:        Andre Oppermann <andre@freebsd.org>
Cc:        "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org>
Subject:   Re: svn commit: r242261 - head/sys/netinet
Message-ID:  <81A9846E-CC54-4822-A5B4-EF37D00B42B3@felyko.com>
In-Reply-To: <508DAA07.9090103@freebsd.org>
References:  <201210281902.q9SJ272D078237@svn.freebsd.org> <6FC10C06-9288-4E2C-A1A2-33C5CC8086C5@felyko.com> <508DAA07.9090103@freebsd.org>

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

> On 28.10.2012 22:34, Rui Paulo wrote:
>> On 28 Oct 2012, at 12:02, Andre Oppermann <andre@FreeBSD.org> wrote:
>>=20
>>> Author: andre
>>> Date: Sun Oct 28 19:02:07 2012
>>> New Revision: 242261
>>> URL: http://svn.freebsd.org/changeset/base/242261
>>>=20
>>> 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.
>>=20
>>=20
>> 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 l=
inks?
>=20
> 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.=20

>=20
> 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.=20=



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