Date: Tue, 2 Feb 2016 09:59:40 +0900 From: Yongmin Cho <yongmincho82@gmail.com> To: hiren panchasara <hiren@strugglingcoder.info> Cc: transport@freebsd.org Subject: Re: Restarting Idle Connections Message-ID: <20160202005939.GA27558@yongmincho-All-Series> In-Reply-To: <20160129215850.GK33155@strugglingcoder.info> References: <20160129043817.GA9865@yongmincho-All-Series> <20160129215121.GJ33155@strugglingcoder.info> <20160129215850.GK33155@strugglingcoder.info>
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I think, This implementation is right. Thank you for the quick reply. :-) On Fri, Jan 29, 2016 at 01:58:50PM -0800, hiren panchasara wrote: > On 01/29/16 at 01:51P, hiren panchasara wrote: > > On 01/29/16 at 01:38P, Yongmin Cho wrote: > > > Hi, all. > > > > > > I have an opinion about net.inet.tcp.initcwnd_segments. > > > You know, snd_cwnd is restarted transmission after a long idle > > > period(Current RTO). > > > And, All of congestion control algorithm is using newreno_after_idle > > > function after a long idle period. > > > But, The newreno_after_idle function is not using initcwnd_segments. > > > I think, The initcwnd_segments should be used in newreno_after_idle > > > function, If the newreno_after_idle is called. > > > I referred to rfc6928. > > > > > > Please check my opinion. > > > > You are absolutely right. We (FreeBSD) adopted initcwnd to be 10 > > segments but never bothered to update newreno_after_idle() function to > > reflect that in calculating cwnd after idle period. Though the comments > > in that function clearly says: > > "The restart window is the initial window or the last CWND, whichever is > > smaller." > > > > I think we should make following change to accommodate it: > > > > diff --git a/sys/netinet/cc/cc_newreno.c b/sys/netinet/cc/cc_newreno.c > > index 97ec35f..5210a45 100644 > > --- a/sys/netinet/cc/cc_newreno.c > > +++ b/sys/netinet/cc/cc_newreno.c > > @@ -166,6 +166,10 @@ newreno_after_idle(struct cc_var *ccv) > > * > > * See RFC5681 Section 4.1. "Restarting Idle Connections". > > */ > > + if (V_tcp_initcwnd_segments) > > + rw = min(V_tcp_initcwnd_segments * CCV(ccv, t_maxseg), > > + max(2 * CCV(ccv, t_maxseg), > > + V_tcp_initcwnd_segments * 1460)); > - if (V_tcp_do_rfc3390) > + else if (V_tcp_do_rfc3390) > > But you get the idea. :-) > > Cheers, > Hiren > > rw = min(4 * CCV(ccv, t_maxseg), > > max(2 * CCV(ccv, t_maxseg), 4380)); > > > > Any inputs? > > > > Cheers, > > Hiren > > > -----BEGIN PGP SIGNATURE----- > > Version: GnuPG v2 > > > > iQF8BAABCgBmBQJWq97WXxSAAAAAAC4AKGlzc3Vlci1mcHJAbm90YXRpb25zLm9w > > ZW5wZ3AuZmlmdGhob3JzZW1hbi5uZXRBNEUyMEZBMUQ4Nzg4RjNGMTdFNjZGMDI4 > > QjkyNTBFMTU2M0VERkU1AAoJEIuSUOFWPt/lf38H/2mwyoYYc0ag1MVE1uzhZ0rL > > K2KTnjZnXFuAw6FLgmUtgNw1ykWD2IjhTmNmzTw03KPmQuKj+FyZUHg78hu4kA/l > > CbaiIO+1EHw9+aT+2yzZgK5yZLdTIF873sBoCdPWUP826WLjhPuxVox0CPOWzhw1 > > XuoSOLYZjsTGysdoMA3AyLOB+ESEC4V1Blf5SocdJPDF0y1Cpes3E6HuXxfix3ee > > kj9bKCZL9jU8DAGZHdT9WwF8qfxqRjzhlOUtzY+3pBxglzXPzlhaxS0mGX/W23Jr > > MHS9NleAh6M0Ot5M8X8WlXxvwqQdfssKAB3m9JIoTxldbqPRjKOhKALcoG8pqHo= > > =TCcb > > -----END PGP SIGNATURE----- >
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