From owner-freebsd-hackers@FreeBSD.ORG Fri Apr 11 07:07:53 2003 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 75D7B37B418; Fri, 11 Apr 2003 07:07:50 -0700 (PDT) Received: from samson.dc.luth.se (samson.dc.luth.se [130.240.112.30]) by mx1.FreeBSD.org (Postfix) with ESMTP id 0886F43FDF; Fri, 11 Apr 2003 07:07:49 -0700 (PDT) (envelope-from bj@dc.luth.se) Received: from dc.luth.se (root@bompe.dc.luth.se [130.240.60.42]) by samson.dc.luth.se (8.12.5/8.12.5) with ESMTP id h3BE7ijY029873; Fri, 11 Apr 2003 16:07:44 +0200 (MET DST) Received: from bompe.dc.luth.se (bj@localhost.dc.luth.se [127.0.0.1]) by dc.luth.se (8.12.6/8.11.3) with ESMTP id h3BE7hKl086838; Fri, 11 Apr 2003 16:07:43 +0200 (CEST) (envelope-from bj@bompe.dc.luth.se) Message-Id: <200304111407.h3BE7hKl086838@dc.luth.se> X-Mailer: exmh version 2.5 07/13/2001 with nmh-1.0.4 To: Mattias Pantzare In-reply-to: Your message of Fri, 11 Apr 2003 15:58:55 +0200. <3E96CA1F.4070000@ludd.luth.se> Dcc: X-Disposition-notification-to: Borje.Josefsson@dc.luth.se X-uri: http://www.dc.luth.se/~bj/index.html Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Date: Fri, 11 Apr 2003 16:07:43 +0200 From: Borje Josefsson cc: freebsd-hackers@freebsd.org cc: freebsd-performance@freebsd.org cc: "Jin Guojun \[DSD\]" cc: Eric Anderson cc: David Gilbert Subject: Re: tcp_output starving -- is due to mbuf get delay? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: bj@dc.luth.se List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 11 Apr 2003 14:07:53 -0000 On Fri, 11 Apr 2003 15:58:55 +0200 Mattias Pantzare wrote: > Terry Lambert wrote: > > Mattias Pantzare wrote: > > = > >>>The products that Jeffrey Hsu and I and Alfred and Jon Mini > >>>worked on at a previous company had no problems at all on a > >>>1Gbit/S saturating the link, even through a VLAN trunk through > >>>Cisco and one other less intelligent switch (i.e. two switches > >>>and a VLAN trunk). > >> > >>A key factor here is that the testst where on a link with a 20ms > >>round-tip time, and using a singel TCP connection. So the switches > >>where in addition to a few routers on a 10Gbit/s network. > > = > > = > > Sorry, but tis is not a factor. If you think it is, then you > > are running with badly tuned send and receive maximum window > > sizes. > > = > > Latency =3D pool retention time =3D queue size > = > Then explain this, FreeBSD to FreeBSD on that link uses all CPU on the = > sender, the reciver is fine, but performance is not. NetBSD to FreeBSD = > fills the link (1 Gbit/s). On the same computers. MTU 4470. Send and = > receive maximum windows where tuned to the same values on NetBSD and = > FreeBSD. I should add that I have tried with MTU 1500 also. Using NetBSD as sender= = works fine (just a little bit higher CPU load). When we tried MTU1500 wit= h = FreeBSD as sender, we got even lower performance. Somebody else in this thread said that he had got full GE speed between = two FreeBSD boxes connected back-to-back. I don't question that, but that= = doesn't prove anything. The problem arises when You are trying to do this= = long-distance and have to handle a large mbuf queue. --B=F6rje