[SATLUG] 10GbE configuration and performance issues

[Daniel J. Givens]

Bruce Dubbs wrote:
> Gregory Alan Hildstrom wrote:
>   
>> Hello. I am working on an application that needs 200MB/s sustained
>> iSCSI throughput for high speed data acquisition.
>>
>>     
>
>   
>> I ran netserver on the server and "netperf -H 192.168.2.151" on the
>> client. I got 1550Mb/s, but I was expecting something more like
>> 3-4Gb/s. CPU load on the slower client machine never got above 25%
>> and I do not know how to measure PCI bus bandwidth utilization.
>>     
>
> I don't know how to solve the network issue, but be sure that your disk
> drives can handle that much data or that you can buffer the data in RAM.
>   
He's writing to a ramdisk, so there is no disk i/o overhead getting in 
the way.

It sounds to me that the PCI bus may be the constraint. If 2128 Mb/s is 
the theoretical max for 32-bit, I would think you're getting close to 
that at 1550Mb/s. With that said, though, you should be running at 
64-bit. Have you checked the output of lspci -vv to see if you can get 
any more info on what the card is running at and what latency is there, 
etc? I'm a little stumped too, given what  you've said already.

One final thought. Are there any settings in the BIOS that might be 
worth checking out? I haven't been into any of our server's BIOSes 
recently, so I have forgotten what all is in there. Oh yeah, once you 
get it figured out, you're going to have to let us know what the fix 
action was.

Good luck!
Daniel