nginx tuning

http://dak1n1.com/blog/12-nginx-performance-tuning

http://blog.martinfjordvald.com/2011/04/optimizing-nginx-for-high-traffic-loads/

http://stackoverflow.com/questions/3436808/how-does-nginx-handle-http-requests

http://stackoverflow.com/questions/6250005/how-can-event-driver-nginx-process-high-concurrent-requests-with-only-2-worker-p