On Mar 17, 2004, at 8:56 PM, Lever, Charles wrote:
> charles-
>
>>> [ snip ]
>>>
>>>
>> We'll see if this disappears after we've finished migrating
>> the network
>> to 1Gbps
>>
>>> In these environments you *must* use TCP, since that has congestion
>>> control capabilities baked into the protocol...
>
> what matters here is flow control. UDP simply doesn't have it.
>
> for gigabit Ethernet, you need flow control at the link level and
> at the transport level. so once you have gigabit infrastructure,
> be sure you have enabled full gigabit flow control on your servers
> and on your switches. then you should use TCP and not UDP so you
> have transport layer flow control.
>
Charles and Trond,
thanks for the advices !
I've upgraded the network cards of the linux machines to Gigabit
ethernet cards and used tcp for my nfs mounts.
The problem disappeard so far so i'm pretty happy !
However i'm very disappointed by the throuhput i'm getting on the Gbps
network :
When i scp a 473991492 bytes file from one machine to the other, i'm
getting 14Mbps throughput, which is far less that 1Gpbs theoretical.
Looking at the network card info ( i'm using the sk98lin driver ) i've :
Mar 18 14:49:15 omnirot kernel: eth0: network connection up using port A
Mar 18 14:49:15 omnirot kernel: speed: 1000
Mar 18 14:49:15 omnirot kernel: autonegotiation: yes
Mar 18 14:49:15 omnirot kernel: duplex mode: full
Mar 18 14:49:15 omnirot kernel: flowctrl: symmetric
Mar 18 14:49:15 omnirot kernel: role: slave
Mar 18 14:49:15 omnirot kernel: irq moderation: disabled
Mar 18 14:49:15 omnirot kernel: scatter-gather: enabled
The switch i'm using is a Netgear GS516T
i've tried transferring to/from 2 linux machines connected to this
switch using the exact same kernel and network cards and also to Mac
Xserv using a Gbps card . They both yield the same low throuput.
Any hint of what could be causing this ?
Thanks in advance.
Charles-Edouard Ruault
Idtect SA
tel: +33-1-42-81-81-84
fax: +33-1-42-81-82-21
http://www.idtect.com