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Date:      Tue, 10 Dec 2002 20:48:50 -0300 (ART)
From:      Fernando Gleiser <fgleiser@cactus.fi.uba.ar>
To:        Doron Shmaryahu <doron@home.crc.co.za>
Cc:        FreeBSD-questions <FreeBSD-questions@freebsd.org>
Subject:   Re: 3c905B drivers
Message-ID:  <20021210204520.F5648-100000@cactus.fi.uba.ar>
In-Reply-To: <007501c2a072$2328d670$0801a8c0@dman>

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On Tue, 10 Dec 2002, Doron Shmaryahu wrote:

> Hi,
>
> I have had two instance's when using the 3com card that the bsd box
> reboot's, when transferring alot of data to it. I have also had machine's

Maybe the NICs were buggy. I've heard some of the early 905s were.

> complete lockup. I now use Realtek 8029/8139 and not a single problem.

I know I wouldn't put a 8131 on a production server, unless I have no
choice.

This comment is from /sys/pci/if_rl.c:

*
 * The RealTek 8139 PCI NIC redefines the meaning of 'low end.' This is
 * probably the worst PCI ethernet controller ever made, with the possible
 * exception of the FEAST chip made by SMC. The 8139 supports bus-master
 * DMA, but it has a terrible interface that nullifies any performance
 * gains that bus-master DMA usually offers.
 *
 * For transmission, the chip offers a series of four TX descriptor
 * registers. Each transmit frame must be in a contiguous buffer, aligned
 * on a longword (32-bit) boundary. This means we almost always have to
 * do mbuf copies in order to transmit a frame, except in the unlikely
 * case where a) the packet fits into a single mbuf, and b) the packet
 * is 32-bit aligned within the mbuf's data area. The presence of only
 * four descriptor registers means that we can never have more than four
 * packets queued for transmission at any one time.
 *
 * Reception is not much better. The driver has to allocate a single large
 * buffer area (up to 64K in size) into which the chip will DMA received
 * frames. Because we don't know where within this region received packets
 * will begin or end, we have no choice but to copy data from the buffer
 * area into mbufs in order to pass the packets up to the higher protocol
 * levels .
 *
 * It's impossible given this rotten design to really achieve decent
 * performance at 100Mbps, unless you happen to have a 400Mhz PII or
 * some equally overmuscled CPU to drive it.


			Fer


>
> Doron Shmaryahu
> ----- Original Message -----
> From: "Christophe Simon" <titof3000@hotmail.com>
> To: <fgleiser@cactus.fi.uba.ar>
> Cc: <freebsd-questions@FreeBSD.ORG>
> Sent: Tuesday, December 10, 2002 5:30 PM
> Subject: Re: 3c905B drivers
>
>
> >
> >
> >
> >
> >
> >
> >
> > >From: Fernando Gleiser <fgleiser@cactus.fi.uba.ar>
> > >To: Christophe Simon <titof3000@hotmail.com>
> > >CC: freebsd-questions@FreeBSD.ORG
> > >Subject: Re: 3c905B drivers
> > >Date: Tue, 10 Dec 2002 12:14:36 -0300 (ART)
> > >
> > >On Tue, 10 Dec 2002, Christophe Simon wrote:
> > >
> > > > Does anyone know about an instability in the 3c90x drivers from 3com
> on
> > > > freeBSD ?
> > >
> > >What problems? I've been using 3C905b for years without any problem.
> > >
> > >
> > >
> > > Fer
> > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > _________________________________________________________________
> > > > MSN Messenger : discutez en direct avec vos amis !
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> > > >
> > > >
> > > > To Unsubscribe: send mail to majordomo@FreeBSD.org
> > > > with "unsubscribe freebsd-questions" in the body of the message
> > > >
> >
> > I have a problem of network instability. I use FreeBSD 4.7 as a file
> server
> > to serve windows machines with samba 3, and i use postfix as mail server.
> 10
> > to 20 minutes after my server starts, the samba and postfix services fall
> > down and don't reply anymore. I am forced to restart my network by
> > /etc/netstart. I try to know if that problem comes from FreeBSD itself, or
> > if there can be a problem with  the origina driver (i know there's some
> > under Linux...)
> >
> > That's why i ask this question...
> >
> > Thanks for replying do quick !
> >
> > _________________________________________________________________
> > MSN Search, le moteur de recherche qui pense comme vous !
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> >
> >
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> >
> >
>
>
>
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