[Users] Performance troubleshooting

Hi, I am having performance issues with openser running on Fedora. Here is the scenario: I have a openser which is sending calls to two asterisks, doing radius accounting and local syslog accounting, the database for user location is a local MySQL and the asterisks are load-balanced through dispatcher. i have modules: loadmodule "/usr/local/lib/openser/modules/mysql.so" loadmodule "/usr/local/lib/openser/modules/sl.so" loadmodule "/usr/local/lib/openser/modules/tm.so" loadmodule "/usr/local/lib/openser/modules/rr.so" loadmodule "/usr/local/lib/openser/modules/maxfwd.so" loadmodule "/usr/local/lib/openser/modules/usrloc.so" loadmodule "/usr/local/lib/openser/modules/registrar.so" loadmodule "/usr/local/lib/openser/modules/nathelper.so" loadmodule "/usr/local/lib/openser/modules/textops.so" loadmodule "/usr/local/lib/openser/modules/xlog.so" loadmodule "/usr/local/lib/openser/modules/avpops.so" loadmodule "/usr/local/lib/openser/modules/avp_radius.so" loadmodule "/usr/local/lib/openser/modules/acc.so" loadmodule "/usr/local/lib/openser/modules/options.so" loadmodule "/usr/local/lib/openser/modules/uri_db.so" loadmodule "/usr/local/lib/openser/modules/auth.so" loadmodule "/usr/local/lib/openser/modules/auth_db.so" loadmodule "/usr/local/lib/openser/modules/auth_radius.so" loadmodule "/usr/local/lib/openser/modules/dispatcher.so" Now the problem is that if i use sipp to send INVITE with 10-20 call attempts per seccond at one time ser just timeouts without answering for 1-2 seconds and sipp has to retransmit the packets. The timeout which sipp waits is 500ms so it should be enough. I have something like on 500 call attempts i get 700 retransmits. I will start stripping the config to troubleshoot but i was wondering if you can give me some idea what the problem might be or some good advice on troubleshooting, where should i look, and if you have any bes practices to recommend. BR, Dimitar