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Date:      Thu, 15 Jun 2000 14:50:53 -0400
From:      "Sean O'Connell" <sean@stat.Duke.EDU>
To:        Dan Yergeau <yergeau@gloworm.Stanford.EDU>
Cc:        FreeBSD mobile <freebsd-mobile@FreeBSD.ORG>
Subject:   if_ed problems [was Re: Netgear ... sigh.]
Message-ID:  <20000615145053.U8955@stat.Duke.EDU>
In-Reply-To: <200006140748.AAA18256@gloworm.Stanford.EDU>; from yergeau@gloworm.Stanford.EDU on Wed, Jun 14, 2000 at 12:48:44AM -0700
References:  <20000614000817.C4496@stat.Duke.EDU> <200006140748.AAA18256@gloworm.Stanford.EDU>

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Dan Yergeau stated:
> Sean O'Connell had written:

[ much snippage]

> >Even though I can get the Linksys 10/100 card to be probed and attached,
> >I get absolutely abyssmal performance out of it (almost like a duplex 
> >mismatch and if_ed doesn't appear to support media/mediaopt settings)
> >on a 10 (only) hub.  
> >
> >scp'ing a good size file may take 25 or 30 seconds
> >using an older card (eg. Linksys EC2T) but will take like 25 minutes
> >using this newer card.   Do you get decent performance out of your 
> >Linksys card?
> I've mostly had it attached to cheapo Netgear EN104 10BaseT hub
> (private home network NAT'd to a PPPoE-based DSL connection).
> Besides the DSL modem and the Linksys PCMPC100, the other NIC on the
> hub is an old 3COM 3C595 Fast Etherlink III PCI, using the vx driver
> (which only supports 10Mbps mode).  I see about 700Kbps in either
> direction between the Linksys PCMPC100 V2 and the Etherlink III, but
> the collision light on the hub is lit solid during these transfers,
> so something isn't working optimally.  IIRC, I was seeing about
> 1.1MBps when connected to a 100Mbps switch (1.5MBps is about the
> limit of any 16-bit PCMCIA network card; to get more you need to go
> with 32-bit CardBus, but I've gotten conflicting stories about the
> extent of CardBus support in 4.0).
> BTW, not only doesn't if_ed not support media/mediaopt, but it also
> doesn't seem to collect statistics (e.g. bytes, good packets,
> collisions, and errors).  Have a look at the output from "netstat -I
> ed0 1".  Note that although the vx does report bytes and packets
> transferred in/out, it doesn't report any collision under the above
> conditions.  With a hub, it should be seeing the collisions.
> Given your performance, if_ed seems to dropping packets in such a
> way that the dropped packets aren't being detected as collisions or
> passed up the network stack (incomplete packets from an
> underrun/overrun).  The only advice I have is to add debugging code
> to the driver to try to figure out why it is dropping packets, then
> file a PR and/or post your findings to freebsd-mobile.


[Note: I am cc'ing FreeBSD mobile ]

I backed if_ed.c (still need the if (1) hack) and if_ed_pccard.c back
to the 4.0-RELEASE code and suddenly, I am getting more reasonable
performance (or at least reasonable performance :).

I will try and see if it is one or the or both, but I just
wanted to let folks know that something is pretty wrong with
some post 4.0-RELEASE code at least as far as the Linksys 10/100
PCM100 (integrated PC Card) is concerned.

Sean O'Connell                                Email: sean@stat.Duke.EDU
Institute of Statistics and Decision Sciences Phone: (919) 684-5419
Duke University                               Fax:   (919) 684-8594

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