Hi all!

I have been doing some performance tests with Kamailio 5.7.4 and SIPp.

The infrastructure is as follows:3 VMs running on VMWare ESXi running: 

UAC on 10.20.0.1 with SIPP-> Kamailio on 10.20.0.5 -> UAS on 10.20.0.3

The Kamailio VM has 6 dedicated vCPU of type Intel(R) Xeon(R) Silver 4216 CPU @ 2.10GHz and, 2 NICs and 4Gb RAM and MariaDB 10.6 as DB Backend., all running on a HP G380 host with a gazillion CPUs and a googol disk space!

I currently have 3 scripts:

- script #1 stateful with RTJson and simulating requests to routing engine and accounting

- script #2 stateful but with just a simple routing to UAS, no rules, no DB, 

- script #3 stateless with a forward to UAS

With script #3 I can go up to 2000CPS without issues with CPU at 37%! Above that value, I get retransmissions everywhere.

On both scripts #1 and #2, the limit is 330CPS max after which I get a lot of retransmissions, while CPU/Core usage on Kamailio server stays below 10%.

So I do not expect this to be a CPU issue.

I could not understand why such (low) results, so I followed this article found at 

and created exact same scenarios, with kamailio script and SIPP templates available on the article, hoping for better results.

But I get the same results: between 300 and 330CPS which is far, very far from the 7000CPS found in the article!

I understand that I'm using VMs and probably the tests made for the article, which is pretty old already, were made on physical servers. Still, I would not expect 95% of lower performance!

Any clue what could be the issue? I suspect NICs, but....

Any tips anyone could share?

Thanks in advance!