I've upgraded one of my servers with ngx_pagespeed 18.104.22.168 and receiving errors when trying to restart nginx. On another server of mine, I have done a fresh installation of CentOS 6 and installed 22.214.171.124 by default. Please note that I downloaded latest version of centminmod before installing on server. New installation is giving me this error - Starting nginx: [0919/050830:INFO:google_message_handler.cc(35)] No threading detected. Own threads: 1 Rewrite, 1 Expensive Rewrite. How to fix that? And what will be the best method to upgrade ngx_pagespeed 126.96.36.199 on a existing server where I have version 188.8.131.52 installed? Some help will be appreciated.