[sr-dev] new memory allocator proposal: TLSF

Hi, == Short story: Currently, there is a (corner case) performance issue in kamailio when lots of fragments of about the same size are freed in a short time. == Long story: I've recently hit a wall using kamailio, dealing with ~150k TLS connections in parallel: when I stop my injector (sipp), all the connections are closed at the same time. The TCP main process took ~20 minutes to dispose of all the objects, and was unable to accept any new connection in the meantime. The bottleneck lies in the shm_free() code (whether f_malloc or q_malloc is used), when a free fragment is be inserted in an ordered linked list (which is O(n) if n is the size of the list). Enabling mem_join did help a little (less fragments, shorter lists), and the 150k disconnections scenario went down to ~5 minutes unavailability for the TCP main process. But this is still big. == TLSF: I looked for alternatives to f/q_malloc, and I found TLSF: * http://www.gii.upv.es/tlsf/ This allocator has O(1) malloc and free even in every case. This means no surprise like the one I had previously. I took the implementation found here: * http://tlsf.baisoku.org/ and integrated it in kamailio. My 150k disconnections scenario went down to 12 seconds, and the fragmentation is as good as q_malloc() with mem_join. I've published a branch with TLSF here: * https://github.com/kamailio/kamailio/commits/tmp/TLSF_malloc What do you think of integrating it in kamailio? By the way, I've tried to play with dl_malloc, ll_malloc and sf_malloc, but none of these currently compile. Should we maintain them or remove them from the codebase? -- Camille