Date: Sun, 28 Oct 2012 23:12:49 +0100 From: Andre Oppermann <andre@freebsd.org> To: Rui Paulo <rpaulo@felyko.com> 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: <508DADE1.6050900@freebsd.org> In-Reply-To: <81A9846E-CC54-4822-A5B4-EF37D00B42B3@felyko.com> References: <201210281902.q9SJ272D078237@svn.freebsd.org> <6FC10C06-9288-4E2C-A1A2-33C5CC8086C5@felyko.com> <508DAA07.9090103@freebsd.org> <81A9846E-CC54-4822-A5B4-EF37D00B42B3@felyko.com>
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On 28.10.2012 23:01, Rui Paulo wrote: > 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: >>> >>>> 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. RFC6298. -- Andre
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