[sr-dev] Asynchronous processing feature set

Hello, I am looking for some recommendations on how to move forward with asynchronous call processing. Our adoption and standardisation of async processing in >= 4.2 into our core product has been a disaster. I don't mean that to sound accusatory; it's open source, there's no reason to blame anyone. It's just a matter of fact. 1) We can't use async_task_route()/the standard async task worker approach in the 'async' module because of this problem, which both Olle and I have reported: http://sr-dev.sip-router.narkive.com/5Sfc5cUU/async-module-cpu-load Most users run Kamailio inside a VM and the problem shows up for ~50% of them. 2) Using t_suspend -> mqueue -> rtimer -> t_continue(), we continue to see deadlocks and occasional crashes. They are rare, and are most likely to happen in high-throughput, short-duration environments, but when they do happen, they're politically disastrous. We've had to roll back use of this method of async processing for pretty much all customers for whom it was enabled. After the last time we visited this issue earlier this spring, the problem has shifted away from crashes and mostly toward deadlocks. Regardless, the customer's enthusiasm for pausing call processing long enough to attach a debugger and grab a backtrace or something like that is exactly 0.0%. I think most of them have more of an enthusiasm for firing us as a vendor than for doing any diagnostic work. I know there's a way to invoke a process in such a way that when it crashes, gdb auto-attaches and pulls a backtrace, then restarts the process. I've written such a wrapper script before in the distant past. I just don't remember how to do it, especially with modern versions of GDB; any suggestions would be appreciated. Otherwise, I don't really know what to do. We need async processing for higher-CPS systems, and would like to standardise upon it in principle, but so far it has, from a strictly functional point of view, been an enormous economic blunder. I still prefer to be an "early adopter" of such novelties - when useful - in high-volume production systems in order to contribute the testing and feedback back to the project. But I have to strike some realistic balance here and not lose the customers. :-) Thanks! -- Alex -- Alex Balashov | Principal | Evariste Systems LLC 303 Perimeter Center North, Suite 300 Atlanta, GA 30346 United States Tel: +1-800-250-5920 (toll-free) / +1-678-954-0671 (direct) Web: http://www.evaristesys.com/, http://www.csrpswitch.com/