On Sat, Jun 8, 2013 at 5:43 AM, Gianluca Oglietti <gianogli@xxxxxxxxxx> wrote: > I've a Supermicro server with a X8DTU-6TF+ matherboard. (You can find the > system block diagram at http://goo.gl/ibWhb). > It is a NUMA system with 2 processors and only one Intel 5520 I/O hub. > In the last weeks I've made some studies about the optimization of the > TCP/IP packets realtime analysis but I've encountered a problem. > All the PCIe interfaces, where are used the NICs, are interconnected, > through the Intel 5520 I/O hub, only to the NUMA node 0: > ... > Is there a way to reconfigure the Intel 5520 I/O hub (via software, > without a new BIOS) to connect one NIC to NUMA node 0 and the other one > to NUMA node 1? There's no standard way to do this via the PCI core, because it's too system-specific. You might be able to learn something by reading the 5520 spec: http://www.intel.com/content/www/us/en/chipsets/5520-5500-chipset-ioh-datasheet.html It sounds like your system is similar to Figure 1-1 in that doc, which looks pretty symmetric. I don't know anything about the 5520 internals, or why there might be preferential routing to NUMA node 0 over node 1. Have you measured a difference in NIC performance between NUMA node 0 and 1? Maybe the I/O connections actually are symmetric, and the BIOS just uses the same distance tables, i.e., whatever determines the local_cpulist contents, for both a single-node and a two-node system? Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
