Hi Bruce, On Mon, Jun 13, 2016 at 4:28 PM, Bruce Richardson <bruce.richardson at intel.com> wrote: > On Mon, Jun 13, 2016 at 04:07:37PM +0200, Take Ceara wrote: >> Hi, >> >> I'm reposting here as I didn't get any answers on the dpdk-users mailing >> list. >> >> We're working on a stateful traffic generator (www.warp17.net) using >> DPDK and we would like to control two XL710 NICs (one on each socket) >> to maximize CPU usage. It looks that we run into the following >> limitation: >> >> http://dpdk.org/doc/guides/linux_gsg/nic_perf_intel_platform.html >> section 7.2, point 3 >> >> We completely split memory/cpu/NICs across the two sockets. However, >> the performance with a single CPU and both NICs on the same socket is >> better. >> Why do all the NICs have to be on the same socket, is there a >> driver/hw limitation? >> > Hi, > > so long as each thread only ever accesses the NIC on it's own local socket, > then > there is no performance penalty. It's only when a thread on one socket works > using a NIC on a remote socket that you start seeing a penalty, with all > NIC-core communication having to go across QPI. > > /Bruce
Thanks for the confirmation. We'll go through our code again to double check that no thread accesses the NIC or memory on a remote socket. Regards, Dumitru
