[Beowulf] Whats up with these newer Intel NICs?

Joe Landman landman at scalableinformatics.com
Sun Sep 23 19:48:11 PDT 2007

Hi folks:

   Working on trying to figure out why the Intel NICs on these 
motherboards we are working with are slow.  Ok, slow is a relative term. 
  More along the lines of "not as fast as they could be" specifically 
relative to a PCI-x 1000/MT adapter we plugged in.

   Scenario is trying to do some load testing.  I have 4 clients, all 
with the same version of OS, pounding on our server (part of the load 
test).  Gigabit, server does channel bonding.  Seeing good results.  But 
.... on the nodes that use this beast:

04:00.0 Ethernet controller: Intel Corporation 80003ES2LAN Gigabit 
Ethernet Controller (Copper) (rev 01)
         Subsystem: Super Micro Computer Inc Unknown device 0000
         Flags: bus master, fast devsel, latency 0, IRQ 1274
         Memory at c8200000 (32-bit, non-prefetchable) [size=128K]
         I/O ports at 2000 [size=32]
         Capabilities: [c8] Power Management version 2
         Capabilities: [d0] Message Signalled Interrupts: Mask- 64bit+ 
Queue=0/0 Enable+
         Capabilities: [e0] Express Endpoint IRQ 0
         Capabilities: [100] Advanced Error Reporting
         Capabilities: [140] Device Serial Number f2-72-32-ff-ff-48-30-00

we get ~70-75 MB/s, while plugging a nice little

05:02.0 Ethernet controller: Intel Corporation 82546GB Gigabit Ethernet 
Controller (rev 01)
         Subsystem: Intel Corporation PRO/1000 MT Dual Port Server Adapter
         Flags: bus master, 66MHz, medium devsel, latency 52, IRQ 28
         Memory at c8340000 (64-bit, non-prefetchable) [size=128K]
         Memory at c8300000 (64-bit, non-prefetchable) [size=256K]
         I/O ports at 3000 [size=64]
         [virtual] Expansion ROM at c2000000 [disabled] [size=256K]
         Capabilities: [dc] Power Management version 2
         Capabilities: [e4] PCI-X non-bridge device

into a PCI-x slot gives us 92-98 MB/s for our load test (IOzone).  It 
gives more than that, I am optically averaging.

Ok.  So the mystery is *why*.

First I note that the first unit, which is a motherboard NIC, has 
"32-bit memory" at a particular address, while the second unit, the 
1000/MT card in the PCI-x slot has "64-bit memory" at a different address.

Second, and this is counter intuitive, but the motherboard gigabit unit 
is on PCI-e (x4 at that!)

> [  115.246121] PCI: Setting latency timer of device 0000:04:00.0 to 64
> [  115.261547] e1000: 0000:04:00.0: e1000_probe: (PCI Express:2.5Gb/s:Width x4) 00:30:48:32:72:f2
> [  115.290791] PM: Adding info for No Bus:eth0
> [  115.290843] e1000: eth0: e1000_probe: Intel(R) PRO/1000 Network Connection
> [  115.290868] ACPI: PCI Interrupt 0000:04:00.1[B] -> GSI 19 (level, low) -> IRQ 19
> [  115.290882] PCI: Setting latency timer of device 0000:04:00.1 to 64
> [  115.306461] e1000: 0000:04:00.1: e1000_probe: (PCI Express:2.5Gb/s:Width x4) 00:30:48:32:72:f3
> [  115.342947] PM: Adding info for No Bus:eth1
> [  115.342983] e1000: eth1: e1000_probe: Intel(R) PRO/1000 Network Connection

while the PCI-x is on, well, PCI-x.  And it should be slower.

> [  115.608773] e1000: 0000:05:02.0: e1000_probe: (PCI:33MHz:64-bit) 00:04:23:9e:36:ca
> [  115.636072] PM: Adding info for No Bus:eth2
> [  115.636105] e1000: eth2: e1000_probe: Intel(R) PRO/1000 Network Connection
> [  115.636129] ACPI: PCI Interrupt 0000:05:02.1[B] -> GSI 29 (level, low) -> IRQ 29
> [  115.902030] e1000: 0000:05:02.1: e1000_probe: (PCI:33MHz:64-bit) 00:04:23:9e:36:cb
> [  115.928619] PM: Adding info for No Bus:eth3
> [  115.928648] e1000: eth3: e1000_probe: Intel(R) PRO/1000 Network Connection
> [  115.928687] ACPI: PCI Interrupt 0000:06:00.0[A] -> GSI 24 (level, low) -> IRQ 24

The driver is 7.3.20-k2-NAPI

> [  110.772712] Intel(R) PRO/1000 Network Driver - version 7.3.20-k2-NAPI
> [  110.772717] Copyright (c) 1999-2006 Intel Corporation.

I know 7.6.5 is out, and I installed it on one of the machines, without 
any impact.

Motherboard is a Supermicro X7DVA-i I think.  I am also seeing this on a 
different Supermicro motherboard with dual cores.  Same issue/performance.

Any thoughts?


Joseph Landman, Ph.D
Founder and CEO
Scalable Informatics LLC,
email: landman at scalableinformatics.com
web  : http://www.scalableinformatics.com
phone: +1 734 786 8423
fax  : +1 866 888 3112
cell : +1 734 612 4615

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