Date: Wed, 22 Oct 2008 07:06:38 +0000 (UTC) From: Lawrence Stewart <lstewart@FreeBSD.org> To: src-committers@freebsd.org, svn-src-projects@freebsd.org Subject: svn commit: r184152 - projects/tcp_cc_8.x/sys/netinet Message-ID: <200810220706.m9M76cnS021741@svn.freebsd.org>
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Author: lstewart Date: Wed Oct 22 07:06:38 2008 New Revision: 184152 URL: http://svn.freebsd.org/changeset/base/184152 Log: Move a comment from tcp_input() into the modular cc code and fold in the New Reno cwnd fix from r182885 that I'd forgotten about. Modified: projects/tcp_cc_8.x/sys/netinet/cc.c projects/tcp_cc_8.x/sys/netinet/tcp_input.c Modified: projects/tcp_cc_8.x/sys/netinet/cc.c ============================================================================== --- projects/tcp_cc_8.x/sys/netinet/cc.c Wed Oct 22 02:08:54 2008 (r184151) +++ projects/tcp_cc_8.x/sys/netinet/cc.c Wed Oct 22 07:06:38 2008 (r184152) @@ -333,8 +333,15 @@ newreno_ack_received(struct tcpcb *tp, s u_int cw = tp->snd_cwnd; u_int incr = tp->t_maxseg; + /* + * If cwnd <= ssthresh, open exponentially (maxseg per packet). + * Otherwise, open linearly (approx. maxseg per RTT + * i.e. maxseg^2 / cwnd per ACK received). + * If cwnd > maxseg^2, fix the cwnd increment at 1 byte + * to avoid capping cwnd (as suggested in RFC2581). + */ if (cw > tp->snd_ssthresh) - incr = incr * incr / cw; + incr = max((incr * incr / cw), 1); tp->snd_cwnd = min(cw+incr, TCP_MAXWIN<<tp->snd_scale); } Modified: projects/tcp_cc_8.x/sys/netinet/tcp_input.c ============================================================================== --- projects/tcp_cc_8.x/sys/netinet/tcp_input.c Wed Oct 22 02:08:54 2008 (r184151) +++ projects/tcp_cc_8.x/sys/netinet/tcp_input.c Wed Oct 22 07:06:38 2008 (r184152) @@ -2093,12 +2093,8 @@ process_ACK: /* * When new data is acked, open the congestion window. - * If the window gives us less than ssthresh packets - * in flight, open exponentially (maxseg per packet). - * Otherwise open linearly: maxseg per window - * (maxseg^2 / cwnd per packet). - * If cwnd > maxseg^2, fix the cwnd increment at 1 byte - * to avoid capping cwnd (as suggested in RFC2581). + * The specifics of how this is achieved are up to the + * congestion control algorithm in use for this connection. */ if (!IN_FASTRECOVERY(tp)) { if (CC_ALGO(tp)->ack_received)
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