[OpenSIPS-Users] Setting opensips for maximum performance

[Jan Rozhon]

Hello,

as a part of my diploma thesis I'm trying to do some performance testing 
of opensips running on low cost machine with 4GB of RAM and dual-core 
AMD Athlon processor. As a generator of SIP traffic I use SIPp v3.1 
running on 4 virtual computers as UAC and two computers as UAS all 
connected just by gigabit ports of a single switch. My proublem is, that 
as soon as I reach the load of 200 calls per second (2000 simultaneous 
calls) many of those calls (aroud 50%) don't finish succesfully. CPU 
utilization of opensips machine is around 40% and memory around 25%, so 
the opensips has still a lot of free resources, but it doesn't use them. 
Could you please advise me, how to change default configuration script 
and opensips settings to achieve better results?

Right now, the only changes I made is :
-enabling registrar/proxy authentication;
-disabled tcp, since all the traffic is carried by udp;
-set shared memory to 2048 MB;
-set number of children to 16
-limit debug level to 1

PS. How can I increase the time, after which opensips retransmits SIP 
messages?

Thanks in advance,
Jan