Re: [E1000-devel] 1000xf bus problem

[Robin Humble <rjh+e1000@cita.utoronto.ca>]

On Mon, Mar 19, 2007 at 06:31:51AM +0100, Willy Tarreau wrote:
>On Sun, Mar 18, 2007 at 11:20:09PM -0600, Robert Hancock wrote:
>> Greg.Chandler@wellsfargo.com wrote:
>> >lspci -v shows the message below, and I am moving files between systems,
>> >{from RAMdisk to RAMdisk} on idle machines.
>> >The transfer rate is concurrent with just under the max throughput
>> >capable on a 64-bit/66Mhz PCI socket.
>> 
>> I think you miscalculate, that bus can transfer 532 MB/sec, Gigabit 
>> Ethernet tops out at 125 MB/sec at absolute maximum and it's difficult 
>> to achieve that in practice.
>
>On TCP payload, you should achieve 118.66 * 10^6 bytes/s ~= 113 MB/s.

times 2 for full duplex.
so a 32bit/33MHz bus = 132MB/s isn't enough for fdx, but anything more
(64bit or 66MHz or both) should be fine.

cheers,
robin

>This is what you should observe with FTP or netcat for instance. On
>local networks, it is perfectly attainable, I do this every day. If you
>are far from this, check both sides link status with ethtool, and ensure
>that you do not have wiring problems. It is usually very easy to fill the
>wire with an e1000.
>
>Also, it would be interesting to check the other side. What card does it
>have, what bus, what driver ? And what software or tests are you using
>to conclude that you're limited by the bus ?
>
>Regards,
>Willy
>
>
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