From owner-freebsd-hackers Fri Nov 30 2:12:13 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from fasterix.frmug.org (s196.dhcp212-198-75.noos.fr [212.198.75.196]) by hub.freebsd.org (Postfix) with ESMTP id 2703F37B416 for ; Fri, 30 Nov 2001 02:12:09 -0800 (PST) Received: (from pb@localhost) by fasterix.frmug.org (8.11.6/8.11.5/pb-20010814) id fAUABuW27707; Fri, 30 Nov 2001 11:11:56 +0100 (CET) (envelope-from pb) Message-ID: <20011130111156.A27621@fasterix.frmug.org> Date: Fri, 30 Nov 2001 11:11:56 +0100 From: Pierre Beyssac To: Leo Bicknell Cc: Josh Paetzel , jc@irbs.com, freebsd-hackers@FreeBSD.ORG Subject: Re: FreeBSD performing worse than Linux? References: <20011128153817.T61580@monorchid.lemis.com> <15364.38174.938500.946169@caddis.yogotech.com> <20011129004234.A16101@exuma.irbs.com> <20011130010354.A21307@fasterix.frmug.org> <20011129184414.F522@twincat.vladsempire.net> <20011130022547.A21889@fasterix.frmug.org> <20011129204225.A63957@ussenterprise.ufp.org> <20011130032345.A23415@fasterix.frmug.org> <20011129222809.A67159@ussenterprise.ufp.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.92.8i In-Reply-To: <20011129222809.A67159@ussenterprise.ufp.org>; from Leo Bicknell on Thu, Nov 29, 2001 at 10:28:09PM -0500 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Thu, Nov 29, 2001 at 10:28:09PM -0500, Leo Bicknell wrote: > > I can't reproduce this result, 16K fills a T1 for 11 ms, which is > > 22000 km (at 2/3 of light speed), enough to get halfway round the > > Your math is a little funny. Right, I knew there was something wrong somewhere :-) > 4000 km one way == 8000 km two way, 8000 / 168300 = 47ms in my book, > theoretial optimum. > > With an RTT of 47ms, you can move 16k per RTT, or or about 340k/sec. It's where I don't quite agree: for a bulk transfer, there is no RTT to account for, you only need to take into account the one-way delay, TCP does the rest for you assuming the window is large enough. Pierre To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message