[SR-Users] EVAPI workload allocation across processes

[Henning Westerholt]

Hello Alex,

I did not looked that closely, sorry. Maybe somebody else can comment as well.

My suggestion would be to try on a small (i.e. low children count) test setup and look e.g. with some "strace" tools inside the process and see actually what is happening.

Cheers,

Henning

-----Original Message-----
From: sr-users <sr-users-bounces at lists.kamailio.org> On Behalf Of Alex Balashov
Sent: Tuesday, January 11, 2022 4:25 PM
To: Kamailio (SER) - Users Mailing List <sr-users at lists.kamailio.org>
Subject: Re: [SR-Users] EVAPI workload allocation across processes

Thanks, Henning! So, does this mean that all messages over a given connection are always received in the same EvAPI worker process? Or does the dispatcher hold the connections, process the messages, and then allocate these messages in a RR/pseudorandom fashion among one or more EvAPI worker processes?

The latter was my understanding, but you said: "The dispatcher process accept(..) the connections and then pass them to the worker processes for further processing.”

That particular formulation had me wondering if the connections themselves are handed off to workers, or just the messages.

— Alex

> On Jan 11, 2022, at 10:09 AM, Henning Westerholt <hw at gilawa.com> wrote:
> 
> Hi Alex,
> 
> not the author of this module - but I think you are right after having briefly looked to the code. The dispatcher process accept(..) the connections and then pass them to the worker processes for further processing. 
> 
> Cheers,
> 
> Henning
> 
> --
> Henning Westerholt – https://skalatan.de/blog/ Kamailio services – 
> https://gilawa.com
> 
> -----Original Message-----
> From: sr-users <sr-users-bounces at lists.kamailio.org> On Behalf Of Alex 
> Balashov
> Sent: Sunday, January 2, 2022 3:54 AM
> To: Kamailio (SER) - Users Mailing List <sr-users at lists.kamailio.org>
> Subject: [SR-Users] EVAPI workload allocation across processes
> 
> Hi,
> 
> Given several EVAPI worker processes:
> 
>   modparam("evapi", "workers", 4)
> 
>   # kamcmd -s /run/kamailio/kamailio_ctl ps | fgrep -i evapi
>   539257	EvAPI Dispatcher
>   539258	EvAPI Worker
>   539259	EvAPI Worker
>   539260	EvAPI Worker
>   539261	EvAPI Worker
> 
> How should one understand the way that the EVAPI workload is allocated among them?
> 
> My best guess is that the EvAPI dispatcher process is the sole accept()or of client connections and the place where all relaying to client connections is done, regardless of their number, and that the ‘workers’ represent an async pool of processes in which TM transactions can be resumed or other work can be done when an outside caller sends a message to the dispatcher.
> 
> However, the documentation[1] is a little vague on the meaning of the ‘workers’ modparam:
> 
>   "Number of worker processes to be started to handle incoming messages from remote applications.”
> 
> Or maybe it’s not. Just wanted to confirm that my understanding is correct.
> 
> Thanks!
> 
> — Alex
> 
> [1] 
> https://kamailio.org/docs/modules/5.5.x/modules/evapi.html#evapi.p.wor
> kers
> 
> --
> Alex Balashov | Principal | Evariste Systems LLC
> 
> Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
> Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
> 
> 
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--
Alex Balashov | Principal | Evariste Systems LLC

Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/


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