From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerrit Renker Subject: Re: [PATCH 3/4] [CCID2]: Replace broken RTT estimator with better algorithm Date: Thu, 28 Feb 2008 09:53:33 +0000 Message-ID: <20080228095333.GA4730@gerrit.erg.abdn.ac.uk> References: <1204122188-9984-1-git-send-email-gerrit@erg.abdn.ac.uk> <1204122188-9984-2-git-send-email-gerrit@erg.abdn.ac.uk> <1204122188-9984-3-git-send-email-gerrit@erg.abdn.ac.uk> <1204122188-9984-4-git-send-email-gerrit@erg.abdn.ac.uk> <5bc4c4570802271840t2b3b12a1k260d1e2d7440bdb2@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: acme@redhat.com, dccp@vger.kernel.org, netdev@vger.kernel.org To: Leandro Sales Return-path: Received: from dee.erg.abdn.ac.uk ([139.133.204.82]:33848 "EHLO erg.abdn.ac.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751597AbYB1Jyl (ORCPT ); Thu, 28 Feb 2008 04:54:41 -0500 Content-Disposition: inline In-Reply-To: <5bc4c4570802271840t2b3b12a1k260d1e2d7440bdb2@mail.gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: | > + * Decay RTTVAR at most once per flight, exploiting that | > + * 1) pipe <= cwnd <= Sequence_Window = W (RFC 4340, 7.5.2) | > + * 2) AWL = GSS-W+1 <= GAR <= GSS (RFC 4340, 7.5.1) | > + * GAR is a useful bound for FlightSize = pipe, AWL is probably | > + * too low as it over-estimates pipe. | > + */ | > + if (after48(dccp_sk(sk)->dccps_gar, hctx->ccid2hctx_rtt_seq)) { | > + if (hctx->ccid2hctx_mdev_max < hctx->ccid2hctx_rttvar) | > + hctx->ccid2hctx_rttvar -= (hctx->ccid2hctx_rttvar - hctx->ccid2hctx_mdev_max) >> 2; | | More than 80 chars in this line! 87 chars. Is this ok? | There are actually 120 characters in this line. The 80-characters constraint has become a recommendation, i.e. it is possible and legal to make exceptions. I kept it in to allow a better comparison to the original TCP code. If anything, it shows how the ubiquitous `hctx->ccid?hctx_' prefixes make it hard to read the code.