Hi,

We use kamailio as a router in our PBX server. The test below causes significant decreasing of free shared memory and 
many "out of memory" errors in kamailio log:

Preconditions: kamailio server with 256Mb of shared memory allocated.

Test actions: run two load testing scripts at the same time: 
  1) 10000 register operations;
  2) 20000 calls (about 300 per sec);

Results: 
    1) memory consumption in peak values:
 - shmem.free_size: 1.8Mb
 - core: 120Mb:
 - build_req_buf_from_sip_req: 12.5Mb
 - msg_lump_cloner: 23.6Mb
 - sip_msg_shm_clone: 84Mb
 - tm module: 118Mb
    2) shmem.free_size parameter back to normal after the test, so it could be concluded that we don't have any memory leaks.

Is it normal behavior or it's possible to do something to increase performance?

PS: the same behaviour occurs for various values of shared memory defined at the start of kamailio server (128Mb, 256Mb, 512Mb etc.).

Thank you,
Andrey