What's interesting here though is that OpenOnload internally can bond together up to six 10G links, before a configuration file change is required to support more. This could mean that a single 12 core server, running a single Nginx instance should be able to adaquately service 90% wire-rate across all six 10G links, or theoretically 54Gbps of web page traffic. Now of course this is assuming everything is in memory, and the rest of the system is properly tuned. Viewed another way this is 4.5Gbps/core of web traffic serviced by Nginx running with OpenOnload on a Solarflare adapter compared to 1.4Gbps/core of web traffic with an Intel 10G NIC. This is a 3X gain in performance for Solarflare over Intel, how is the possible?
Simple, OpenOnload is a user space stack that communicates directly with the network adapter in the most efficient manner possible to service UDP & TCP requests. The latest version of OpenOnload has also been tuned to address the C10K problem. What's important to note, is that by bypassing the Linux OS to service these communication requests Solarflare reduces the number of kernel context switches/core, memory copies, and can more effectively utilize the processor cache. All of this translates to more available cycles for Nginx on each, and every core.
To further drive this point home we did an additional test just showing the performance gains OOL delivered to Nginx on 40GbE. Here you can see that the OS limits Nginx on a 10-core system to servicing about 15Gbps. With the addition of just OpenOnload to Nginx that number jumps to 45Gbps. Again another 3X gain in performance.
If you have web servers today running Nginx, and you want to give them a gargantuan boost in performance please consider Solarflare and their OpenOnload technology. Imagine taking your existing web server today which has been running on a single Intel x520 dual port 10G card, replacing that with a Solarflare SFN7122F card, installing their OpenOnload drivers and seeing a 3X boost in performance. This is a fantastic way to breath new life into existing installed web servers. Please consider contacting Solarflare today do a 10G OpenOnload proof of concept so you can see these performance gains for yourself first hand.