Re: [Weird problems with INTEL Ethernet Card]
ea@sellinet.net wrote:
>Hello,
>
>
>My ethernet card was on 32bit/33mhz PCI slot. Now it is on 64bit/66mhz
>PCI-X slot. Is there someone that can tell me why I can't get througput
>performance x2? As far as I know if I get 400Mbps+(TX) and 300Mbps+(RX) on
>32bit/33mhz PCI, then If I put my card on 64bit/66mhz PCI-X I should get
>more througput not less right? But in practic I get less traffic througput
>than more. If I use Ethernet Cards that are integrated on the motherboard
>then I don't have any problems and everything work as expected. Also on
>PCI 32bit/33mhz when I reach around 700mbps I get high latency and packets
>loss. The same situation on PCI-X 64bit/66mhz when I reach around
>600mbps+.
>
>PCI 32bit/33mhz: max. over 700mbps both directions.
>PCI-X 64bit/66mhz: max. around 600mbps+ both directions.
>
>
>Distro: Debian
>Kernel: 2.6.15
>RAM: 2G Kingston DDR2 400mhz ECC
>CPUs: 2xXeon 3.2Ghz 800FSB 1mb l2 cache
>
>
># Intel Ethernet Card #
>
>Model: PWLA8490MT
>Chipset: 82545GM
>
>http://www.intel.com/network/connectivity/products/pro1000mt_
>
>server_adapter.htm
>
># SuperMicro MotherBoard #
>
>Model: X6DAL-B2
>
>http://www.supermicro.com/products/motherboard/Xeon800/E7525/X6DAL-B2.cfm
>
>
>
>P.S. Any help or suggestions will be appreciated. Thanks in advanced!
>
>
>
>
Because the link you posted for the motherboard doesn't give specifics
about the PCI-X bus layout it's difficult to be sure whats going on
here. It could be that you have moved the card from the realitivly empty
PCI but to a realitivly full PCI-X bus. Judging by the numbers you post
is possible that the 2 onboard GigE NICs are physically connected to the
same PCI-X bus as the slots on the motherboard, so you are in effect
going from a mostly empty 133MB/sec but to a mostly full 512MB/sec bus
because of the use of the other NICs that are also connected using that bus.
It is possible the 2 PCI-X slots on the board are actually connected to
different buses so you could try the other slot, overall though I would
say that is unlikely. Also you don't mention if you have anything in
that other slot already, if you have a SCSI/RAID card in that slot then
that will only make things worse.
Usually on boards like this the on-board NICs are connected to their own
66Mhz/64Bit bus, and the slots are connected to another bus, which makes
me think you do have another controller of some kind in the second PCI-X
slot
Dave
Reply to: