Howto know my eth0 use PCI-X or PCI-express?

montyleesam · 08-04-2008, 09:28 AM

Hello all.

I use Dell 2950 and ethernet card is Broadcom NetXtreme II BCM5708 1000Base-T.(bnx2)

As I know, PCI-E is more fast and more bandwidth than PCI-X.
than is it good to use PCI-Express supported card than PCI-X
to improve performance?

below is a lspci result of my server and I can see this line.

06:00.0 PCI bridge: Broadcom EPB PCI-Express to PCI-X Bridge (rev c3)

this means my card is PCI-X or PCI-Express type?

Thanks in advance.

02:00.0 PCI bridge: Broadcom EPB PCI-Express to PCI-X Bridge (rev c3)
03:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5708 Gigabit Ethernet (rev 12)
04:00.0 PCI bridge: Intel Corporation 6311ESB/6321ESB PCI Express Upstream Port (rev 01)
04:00.3 PCI bridge: Intel Corporation 6311ESB/6321ESB PCI Express to PCI-X Bridge (rev 01)
05:00.0 PCI bridge: Intel Corporation 6311ESB/6321ESB PCI Express Downstream Port E1 (rev 01)
05:01.0 PCI bridge: Intel Corporation 6311ESB/6321ESB PCI Express Downstream Port E2 (rev 01)
06:00.0 PCI bridge: Broadcom EPB PCI-Express to PCI-X Bridge (rev c3)
07:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5708 Gigabit Ethernet (rev 12)
0e:0d.0 VGA compatible controller: ATI Technologies Inc ES1000 (rev 02)

checkmate3001 · 08-04-2008, 09:44 AM

I would open it up and take a look. PCI express is likely a small connector (but it depends on x16 x24 etc.). PCI X would be a larger connector - like the size of a agp.
Check this wikipedia:
PCI X:
http://en.wikipedia.org/wiki/PCI-X

PCI Express:
http://en.wikipedia.org/wiki/PCI_Express

smoked kipper · 08-04-2008, 01:39 PM

Having a butcher's is certainly the easiest way (unless you have no direct access).

For a software solution, lshw should show you the topology.

farslayer · 08-04-2008, 02:19 PM

Opening the system won't tell you anything since those NIC's are embedded on the motherboard. .I agree lshw should do the trick..

note: this output is NOT from a Dell 2950

Code:

 *-pci:4
             description: PCI bridge
             product: 5000 Series Chipset PCI Express x4 Port 6
             vendor: Intel Corporation
             physical id: 6
             bus info: pci@00:06.0
             version: 93
             width: 32 bits
             clock: 33MHz
             capabilities: pci normal_decode bus_master cap_list
             configuration: driver=pcieport-driver
           *-pci
                description: PCI bridge
                product: EPB PCI-Express to PCI-X Bridge
                vendor: Broadcom
                physical id: 0
                bus info: pci@02:00.0
                version: c2
                width: 32 bits
                clock: 33MHz
                capabilities: pci normal_decode bus_master cap_list
              *-network
                   description: Ethernet interface
                   product: NetXtreme II BCM5708 Gigabit Ethernet
                   vendor: Broadcom Corporation
                   physical id: 0
                   bus info: pci@03:00.0
                   logical name: eth0
                   version: 11
                   serial: 00:19:bb:xx:xx:xx
                   width: 64 bits
                   clock: 66MHz
                   capabilities: bus_master cap_list ethernet physical
                   configuration: broadcast=yes driver=bnx2 ip=172.16.1.22 latency=64 mingnt=64 multicast=yes
                   resources: iomemory:f8000000-f9ffffff irq:130
        *-pci:5
             description: PCI bridge
             product: 5000 Series Chipset PCI Express x4 Port 7
             vendor: Intel Corporation
             physical id: 7
             bus info: pci@00:07.0
             version: 93
             width: 32 bits
             clock: 33MHz
             capabilities: pci normal_decode bus_master cap_list
             configuration: driver=pcieport-driver
           *-pci
                description: PCI bridge
                product: EPB PCI-Express to PCI-X Bridge
                vendor: Broadcom
                physical id: 0
                bus info: pci@04:00.0
                version: c2
                width: 64 bits
                clock: 33MHz
                capabilities: pci normal_decode bus_master cap_list
                resources: iomemory:220001f10-220001f0f
              *-network DISABLED
                   description: Ethernet interface
                   product: NetXtreme II BCM5708 Gigabit Ethernet
                   vendor: Broadcom Corporation
                   physical id: 0
                   bus info: pci@05:00.0
                   logical name: eth1
                   version: 11
                   serial: 00:19:bb:xx:xx:xx
                   width: 64 bits
                   clock: 66MHz
                   capabilities: bus_master cap_list ethernet physical
                   configuration: broadcast=yes driver=bnx2 latency=64 mingnt=64 multicast=yes
                   resources: iomemory:fa000000-fbffffff irq:82

With the bus for the NIC running at 66Mhz I would say these NIC's are on PCI-X per the links provided by Checkmate

Also if you look at the progression it goes: PCI Express x4 -> PCI-Express to PCI-X Bridge -> Broadcom NIC

your output may vary.

checkmate3001 · 08-04-2008, 02:58 PM

So I understand from Farslayer's example.
It is a PCI-Express to PCI-X Bridge. Does that mean that it IS PCI-X not PCI-Express?
Just to clarify, the "to <whatever>" means it is the <whatever> part?

Man I write confusing questions... I hope you understand.

farslayer · 08-04-2008, 03:09 PM

Yes, they are using a bridge to step down from PCI-Express to PCI-X.

so in the example I posted the NIC is effectively connected to a PCI-X bus.

The link you posted to the wikipedia entry showed a PCI-X bus runs at 66Mhz which is another good indicator that it is a PCI-X bus the NIC is connected to.