Thorsten, I have just downloaded the whole PDF to quickly review it. It would have been nice to see what you could take out of haproxy 1.4 which has keep-alive enabled. You're typically in an environment where this difference matters. Also, 1.4 has a few options to save some TCP packets (tcp-smart-accept and tcp-smart-connect), which can reduce a session from 10 to 7 packets. This could potentially mean 2 packets per request with keep-alive on the client, and 7 packets per response without keep-alive on the server, or about 9 packets. We could dream of something like 9000 requests per second if you're limited to 100kpps. Do not hesitate to drop me a mail when you plan other tests, I'm very interested in helping for the tuning!