Date: Tue, 12 Jul 2005 19:20:42 +0900 (JST) From: Noritoshi Demizu <demizu@dd.iij4u.or.jp> To: David Malone <dwmalone@maths.tcd.ie> Cc: freebsd-net@freebsd.org, freebsd-stable@freebsd.org, Luigi Rizzo <rizzo@icir.org> Subject: Re: tcp troughput weirdness Message-ID: <20050712.192042.63502865.Noritoshi@Demizu.ORG> In-Reply-To: <200507121048.ab72454@salmon.maths.tcd.ie> References: <E1DsGx9-0008Xc-GW@cs1.cs.huji.ac.il> <200507121048.ab72454@salmon.maths.tcd.ie>
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(I am sorry if you have received this e-mail. I'm resending this because it seems the previous one was lost.) > TCP inflight limiting is supposed to guess the bandwidth-delay > product for a TCP connection and stop the window expanding much > above this. (Just to clarify..) TCP inflight limiting has a dedicated variable "snd_bwnd". And min(tp->snd_wnd, tp->snd_cwnd, tp->snd_bwnd) limits the amount of data to be sent. > However, some of the guys I know that work on TCP dynamics reckon > that they can they can come up with situations where inflight > limiting will break. Unfortunately, I haven't had time to talk > this through with them. I guess you may have found one of those > situations ;-) I experienced such situations with DragonFlyBSD. I put examples where inflight limiting reduces throughputs at the following pages. http://www.demizu.org/~noritosi/memo/2005/0706/ http://www.demizu.org/~noritosi/memo/2005/0711/ Sorry, all senders in those examples are DragonFlyBSD. Regards, Noritoshi Demizu
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