From owner-freebsd-stable Tue Apr 3 4: 7:26 2001 Delivered-To: freebsd-stable@freebsd.org Received: from point.osg.gov.bc.ca (point.osg.gov.bc.ca [142.32.102.44]) by hub.freebsd.org (Postfix) with ESMTP id BEC4337B718 for ; Tue, 3 Apr 2001 04:07:22 -0700 (PDT) (envelope-from Cy.Schubert@uumail.gov.bc.ca) Received: (from daemon@localhost) by point.osg.gov.bc.ca (8.8.7/8.8.8) id EAA10719; Tue, 3 Apr 2001 04:07:11 -0700 Received: from passer.osg.gov.bc.ca(142.32.110.29) via SMTP by point.osg.gov.bc.ca, id smtpda10717; Tue Apr 3 04:06:58 2001 Received: (from uucp@localhost) by passer.osg.gov.bc.ca (8.11.2/8.9.1) id f33B6l870839; Tue, 3 Apr 2001 04:06:47 -0700 (PDT) Received: from cwsys9.cwsent.com(10.2.2.1), claiming to be "cwsys.cwsent.com" via SMTP by passer9.cwsent.com, id smtpdD70837; Tue Apr 3 04:06:26 2001 Received: (from uucp@localhost) by cwsys.cwsent.com (8.11.3/8.9.1) id f33B6PA02869; Tue, 3 Apr 2001 04:06:25 -0700 (PDT) Message-Id: <200104031106.f33B6PA02869@cwsys.cwsent.com> Received: from localhost.cwsent.com(127.0.0.1), claiming to be "cwsys" via SMTP by localhost.cwsent.com, id smtpdQp2050; Tue Apr 3 04:05:32 2001 X-Mailer: exmh version 2.3.1 01/18/2001 with nmh-1.0.4 Reply-To: Cy Schubert - ITSD Open Systems Group From: Cy Schubert - ITSD Open Systems Group X-Sender: schubert To: Bert Driehuis Cc: "Jason T. Luttgens" , freebsd-stable@FreeBSD.ORG Subject: Re: Network performance question In-reply-to: Your message of "Tue, 03 Apr 2001 01:18:42 +0200." Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Tue, 03 Apr 2001 04:05:31 -0700 Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In message , Be rt Driehuis writes: > On Mon, 2 Apr 2001, Jason T. Luttgens wrote: > > > However - I noticed something while testing. Linux 2.4.3 did not access the > > drive as much as FreeBSD was. I guess Linux is caching the file more or > > something...who knows. So I re-performed the tests with output going to > > /dev/null and looking at the tcpdump and interface counters (I know, it's > > not the best way, but at this point I was thinking it's the disk I/O that's > > causing the drops/loss). > > You could try enabling softupdates if you haven't done so yet. For > benchmarking purposes, you could also try async mount (but note that > async can screw up your disk real bad in case of a system crash). If you want to make all things as equal as possible, you will have to mount async. According to Kirk's paper on Softupdates, Softupdates was about 3% slower than async mounts and a lot faster than SMD mounts. Does anyone on this list have a pointer to the paper so I could reread it? Would it be possible to include it in /usr/share/doc/papers? > > I would not expect either to have much effect if the machine is > otherwise quiescent, but if you are being hit because of any synchronous > activity going on it would be nice if this could be eliminated from the > equation. Depending on how heavy the traffic was at the time you were capturing packets I would think that softupdates or async mounts would have made a big difference. > > Note that you really are entering a grey area here -- it may well be > that the respective kernels have different priorities or strategies that > have little to do with Ethernet performance, e.g. FreeBSD's insistence > (by default) that file systems remain consistent in case of a system > crash might cause some packets to be lost in this flat out. worst case > scenario. It is unlikely that you will prove what happens unless you > stumble upon something that eliminates the difference. Until we have a level playing field, it's a comparison between apples and oranges. Regards, Phone: (250)387-8437 Cy Schubert Fax: (250)387-5766 Team Leader, Sun/Alpha Team Internet: Cy.Schubert@osg.gov.bc.ca Open Systems Group, ITSD, ISTA Province of BC To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message