From owner-freebsd-net Sun Dec 22 22:52:37 2002 Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id E2CB737B401; Sun, 22 Dec 2002 22:52:35 -0800 (PST) Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id 874F343EDA; Sun, 22 Dec 2002 22:52:35 -0800 (PST) (envelope-from dillon@apollo.backplane.com) Received: from apollo.backplane.com (localhost [127.0.0.1]) by apollo.backplane.com (8.12.5/8.12.5) with ESMTP id gBN6qZOM035237; Sun, 22 Dec 2002 22:52:35 -0800 (PST) (envelope-from dillon@apollo.backplane.com) Received: (from dillon@localhost) by apollo.backplane.com (8.12.5/8.12.5/Submit) id gBN6qZmI035236; Sun, 22 Dec 2002 22:52:35 -0800 (PST) (envelope-from dillon) Date: Sun, 22 Dec 2002 22:52:35 -0800 (PST) From: Matthew Dillon Message-Id: <200212230652.gBN6qZmI035236@apollo.backplane.com> To: "matthew c. mead" Cc: Robert Watson , freebsd-net@FreeBSD.ORG Subject: Re: TCP interactions (was: Re: Linux and FreeBSD poor network performance) References: <20021221165745.A67089@goof.com> <20021222151259.A21189@goof.com> <200212222106.gBML6INI032302@apollo.backplane.com> <20021222230527.A30324@goof.com> Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org : :Hmm, same cables, same switch, different card, now it all works. : :I did do some ICMP ping testing with ping -f and only lost 3 :packets after letting it run for a good 10s. : : :-matt If it is working properly you should not lose *ANY* packets on an otherwise idle connection, except possibly the last one that the ping was sending when you ^C'd it (and sometimes ping doesn't wait long enough on the last packet when you give it a specific count). So at most it should report one lost packet over any period of time. Certainly not 3. e.g. workstation# ping -c 1000 -i 0.05 apollo ... 1000 packets transmitted, 1000 packets received, 0% packet loss round-trip min/avg/max/stddev = 0.148/0.159/0.248/0.009 ms If you think about it, 3 lost packets in 10 seconds is one lost packet every 3 seconds or so. That could have an adverse effect on tcp throughput depending on whether NewReno/fast-retransmit is working or not. But even with all the algorithms working properly packet loss can slow TCP down. -Matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message