Thanks, Daniel. So, does this mean that the module "reserves" a "workers" number of common async_workers for its exclusive use? Or do those async_workers just receive whatever they are sent from any number of modules? In that case, what exactly is the role of the "workers" parameter? To limit the number of async_workers to which the module will send requests?
On 24 October 2014 09:15:19 GMT-04:00, Daniel-Constantin Mierla miconda@gmail.com wrote:
On 23/10/14 04:03, Alex Balashov wrote:
Also, what is the point of core async_workers setting versus the 'workers' modparam to async? Are they supposed to equal each other? Does one override the other?
async_workers from core are common for all modules, being a decision not to have each module that wants async operations to create its own pool of processes. The workers defined by async module are only for that module and used only by async_route() and async_sleep().
The implementation is also different, the async module workers are more like timer processes (because both of async_route() and async_sleep() need to sleep some interval of time). The module itself keeps the lists of tasks in a structure optimized for timer execution. Each of this async module workers check from time to time to see if there is a task to be executed, executes what matches the time, then sleeps again for 100ms (iirc), then checks again...
The async_workers from core were designed to receive the job immediately. Because of that, there is an interprocess communication based on sockets in memory. The async workers are listening on them, so once a sip worker sends the task to them, an async worker will receive it.
Hopefully I was able to explain it enough to understand what happens behind.
Cheers, Daniel
On 10/22/2014 09:36 PM, Alex Balashov wrote:
Hi,
What is the practical limit to the number of async worker processes?
With SIP child processes, it seems to be about the number of
available
CPUs in /proc/cpuinfo. After that--at least, per my testing--one
begins
to hit the point of diminishing returns, presumably due to SHM IPC
and
synchronisation issues.
Is the restriction similar in the async execution context?
-- Sent from my mobile, and thus lacking in the refinement one might expect from a fully fledged keyboard.
Alex Balashov - Principal Evariste Systems LLC 235 E Ponce de Leon Ave Suite 106 Decatur, GA 30030 United States Tel: +1-678-954-0671 Web: http://www.evaristesys.com/, http://www.alexbalashov.com