From owner-freebsd-transport@freebsd.org Fri Oct 30 06:24:25 2015 Return-Path: Delivered-To: freebsd-transport@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id EC83BA21D28 for ; Fri, 30 Oct 2015 06:24:25 +0000 (UTC) (envelope-from hiren@strugglingcoder.info) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id D3C041355 for ; Fri, 30 Oct 2015 06:24:25 +0000 (UTC) (envelope-from hiren@strugglingcoder.info) Received: by mailman.ysv.freebsd.org (Postfix) id D10D4A21D27; Fri, 30 Oct 2015 06:24:25 +0000 (UTC) Delivered-To: transport@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id CFA99A21D26 for ; Fri, 30 Oct 2015 06:24:25 +0000 (UTC) (envelope-from hiren@strugglingcoder.info) Received: from mail.strugglingcoder.info (strugglingcoder.info [65.19.130.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mail.strugglingcoder.info", Issuer "mail.strugglingcoder.info" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id B98051354 for ; Fri, 30 Oct 2015 06:24:25 +0000 (UTC) (envelope-from hiren@strugglingcoder.info) Received: from localhost (unknown [10.1.1.3]) (Authenticated sender: hiren@strugglingcoder.info) by mail.strugglingcoder.info (Postfix) with ESMTPA id A97F610BF12; Thu, 29 Oct 2015 23:24:23 -0700 (PDT) Date: Thu, 29 Oct 2015 23:24:23 -0700 From: hiren panchasara To: Randall Stewart Cc: FreeBSD Transports Subject: Maintaining dupack counter per hole (was: The trouble with sack..) Message-ID: <20151030062423.GB5261@strugglingcoder.info> References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="3+nIULlytNYGw3fk" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-BeenThere: freebsd-transport@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Discussions of transport level network protocols in FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 30 Oct 2015 06:24:26 -0000 --3+nIULlytNYGw3fk Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable (Something Randall and I discussed today) On 10/07/15 at 12:17P, Randall Stewart via freebsd-transport wrote: >=20 > 3) When we have more than one hole the goal of SACK was to retransmit eve= ry time that > a hole had 3 dup-acks so that one could recover multiple blocks that = were lost. We just > plain don?t track dup-acks per hole. We do continue to count, but we = will wait to retransmit > anything until after we have drained 1/2 the data in flight from the = network at a minimum. And only then > do we start incrementing cwnd (remember we crashed it to 1 MTU) so th= at we can retransmit. There > may be some other twists in the code that we are missing but this is = what we believe (this could could > probably win the C obfuscation contest if someone were willing to ent= er it :-D) Wondering if we can add this dupack counter in struct sackhole {} and every time we process acks with sack in tcp_sack_doack(), we increment this counter if the same hole appears again. And retransmit it on (or after?) 3rd dupack. Cheers, Hiren --3+nIULlytNYGw3fk Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQF8BAABCgBmBQJWMw0TXxSAAAAAAC4AKGlzc3Vlci1mcHJAbm90YXRpb25zLm9w ZW5wZ3AuZmlmdGhob3JzZW1hbi5uZXRBNEUyMEZBMUQ4Nzg4RjNGMTdFNjZGMDI4 QjkyNTBFMTU2M0VERkU1AAoJEIuSUOFWPt/l6CIH+wX47Sl9L2S+fYio2j1vqapF bk1obggQoLcqn5a3+O+O+XPzYk2oeHlJl4KM6Yx454LuQ2FybNOpeW31zmPrKMqx 2aOmRP+AiLJti7367yQRNvy7r7gvlzaViBRCWBTUm0qZ2QW3ZpYGv684m2n80G7i L/WSI16Ih2W/eRoLkfdQFxby/Wy+LkYWv7eiqLplLU6JP1w7IdBdsTPA7dpVICWJ gaEfrokA69138AzMHg9wB9urx0qoKzNXXprq1vOo2IAHXF8oWfAhtlWi3qK7pk14 Bpv9ULV+Ow7ybWdmUwRdBoQ/JQDh4UQ/8Pom0GkD+0BhaL6Gc4d8KQGCY0sHWA4= =Wa8D -----END PGP SIGNATURE----- --3+nIULlytNYGw3fk--