Hello Kelvin,
I somehow missed your reply.
On Tue, 2010-02-16 at 15:02 -0500, Kelvin Ku wrote:
Did it help?
I switched to an 82576 NIC. The kernel igb driver (version 1.3.16-k2) has multiqueue enabled by default with 4 rx and 4 tx queues. I'm running with 4096 rx ring entries enabled.
The target app is performing well on the igb NIC whereas on the e1000e NIC it was missing packets. I say "missing" rather than "dropped" because these packets don't show up on any error counters. However, in throughput testing, we can't receive faster than 905-910 Mbps whereas we can reliably receive at 950 Mbps on our older non-Nehalem machines.
You should see the missing package using $ ethtool -s. (Most likely rx_missed_errors)
I usually disable power management. Be advised, that we are using 10GbE cards and not 1GbE, so we are more vulnerable to scaling-the-core-down-right-when-the-cards-starts-flooding-the-hell-out-of-it...
I notice that ASPM is enabled on the 82576 NIC and the PCIe ports. Have you disabled ASPM? Disabling C-STATE had no effect on throughput or app performance.
At 1Gbps, it shouldn't. We have ASPM enabled on quad-1GbE and 10GbE without an issue.
I'm going to test with ASPM disabled later today.
P.S. Please post your complete hardware configuration. (Board, CPU, in-which slot did you put the NIC, etc)
I've attached dmidecode and lspci output. Here's a summary:
Motherboard: Supermicro X8DTL-iF CPU: Single Xeon E5530 RAM: 3x1GB 1333MHz DDR3 ECC Registered
The 82576 NIC is inserted into a PCIe 2.0 x8 slot.
The weird things is that a two PCI-E 1.0 channels should be more-than to drive a dual port 1GbE card - let alone 8x/2.0... I'm stumped.
Side question: Why did you buy an expensive dual socket board, and dual socket capable CPU (Xeon 55xx) to run a single CPU? If you don't need the extra codes (or memory), a normal desktop X58/Core i5/i7 will be just as good and far less expensive.
- Gilboa