From owner-freebsd-stable  Wed Mar 21 12:54:37 2001
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Date: Wed, 21 Mar 2001 21:45:26 +0100 (CET)
From: Jan Conrad <conrad@th.physik.uni-bonn.de>
To: Helge Oldach <Helge.Oldach@de.origin-it.com>
Cc: <bright@wintelcom.net>, <dillon@earth.backplane.com>,
	<gordont@bluemtn.net>, <rdm@cfcl.com>, <freebsd-stable@FreeBSD.ORG>
Subject: Re: NFS performance
In-Reply-To: <200103211955.UAA03416@galaxy.de.cp.philips.com>
Message-ID: <Pine.BSF.4.33.0103212133210.559-100000@merlin.th.physik.uni-bonn.de>
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On Wed, 21 Mar 2001, Helge Oldach wrote:

> Jan Conrad:
> >client:
> >Name  Mtu   Network       Address            Ipkts Ierrs    Opkts Oerrs Coll
> >fxp0  1500  <Link#1>    00:02:b3:1f:f8:c5  1901001     0   771611     0 208240
> >server:
> >Name  Mtu   Network       Address            Ipkts Ierrs    Opkts Oerrs Coll
> >fxp0  1500  <Link#1>    00:90:27:1c:f3:79  7157753     0  4648694     0 2661459
>
> Gimme a break. Out of 4648694 output packets you see as many as 2661459
> collisions? That's more than 50%, i.e. for about every second packet
> that you are sending you get a collision! You very clearly have a
> collision problem.
>
> I bet that the switch is at full-duplex while you're at half. Try
> changing the mediaopt setting of your NIC.

That's funny, eh :-)

ok - just collect some facts:

- the switch is configured to 100baseTX, half-duplex: BayStack 450 24T
  (I am not the admin of that thing and have no access to the confs,
   but at least I know how the ports are configured, unfortunately there
   are no full/half duplex lights anymore on the newer Baystacks)
- if I leave it at half-duplex the net makes 9Mb/s
  ping -f <Machine on the same switch) I get 0% to 1% packet loss
  (after relaxing the icmp bandwidth control...)
- if I switch the fxp0 interface to full duplex
  and boot the machine and disconnect the net for some seconds
  the net slows down to 200kb/s

I would conclude that the switch is on 100baseTX, half-duplex, indeed.

again, running on half-duplex, transfering 100Mb from a client to this
machine (merlin)
on client:
mount -t nfs -o intr,nfsv3,-r=32768,-w=32768 merlin:/freebsd/misc /mnt
dd if=/dev/zero of=/mnt/zero bs=16k count=64x100
104857600 bytes transferred in 12.765062 secs (8214422 bytes/sec)

at the same time, netstat -I fxp0 -w 1 gives me

        11     0        668         11     0        412     0
         6     0       1670          5     0       1556     0
         8     0        180          7     0          0     0
        11     0    5155696          8     0      62530     0
       254     0    7015588         23     0      98848    32
      6115     0    7926312        540     0     118592  1189
            input         (fxp0)           output
   packets  errs      bytes    packets  errs      bytes colls
      5304     0    9183810        548     0     136772  1030
      5768     0    8091074        586     0     120418  1139
      6527     0    9191418        674     0     138720  1337
      5915     0    8728739        612     0     129630  1176
      6492     0    9032044        678     0     133856  1243
      6195     0    8112222        634     0     122300  1237
      6509     0    9251329        674     0     137258  1287
      5886     0    8317303        605     0     125380  1138
      6490     0    8904250        665     0     132046  1334
      5978     0    8857169        617     0     139924  1149
      6444     0     853656        676     0      23624  1259
      4720     0        313        564     0          0   903
         1     0       1349          1     0       1390     0
         2     0        171          0     0         90     0


quite funny, but it works :-)

Has anybody ever seen something like that ?
>
> Helge
>
ciao
	Jan


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