I'm using an Asus P5N-T Deluxe motherboard with a 10Gb ethernet controller in the PCI express slot. I have a performance issue that I believe is being caused by a small (128 byte) Max Payload Size on the PCIe. I've noticed that other BIOS' provide an option for changing the PCIe Max Payload Size. The one on this board does not. Is anyone familiar enough with this Motherboard and chipset (NVIDIA nForce 780i) to know if there is a bios update available for it that will add this configuration option? Is this board capable of Max Payload Size > 128?
Thanks for the link, definitely good information. I have tuned the Ethernet buffers and other parameters already. The paper is interesting for average Ethernet traffic, but the tests I am running line up closer with the storage profile described in the paper. One (or less) interrupt per 64kB packet, and the test uses only 64 kB packets. Per that profile, I should see improvement going from 128 to 256, and again from 256 to 512 if I can get it to function with the increased Max_Payload_Size. Right now, when I configure the Ethernet card to something larger than 128 the system hangs with no diagnostic output and must be power cycled to recover it.