[Kamailio-Devel] [SR-Dev] register_timer versus register_timer_process

[Ovidiu Sas]

Should I understand that in ser there are two timer processes:
 - fast timer
 - slow timer

If this is correct, I would like to have the ability to register an
extra process for particular timer.
On a multicore platform, several timers can be processed in parallel.
Under heavy load, I experienced issues while using the standard timer
process for the ratelimit module and therefore I registered the
ratelimit timer with it's own process.


Regards,
Ovidiu Sas

On Mon, Mar 9, 2009 at 9:27 PM, Jan Janak <jan at iptel.org> wrote:
> On 09-03 21:19, Ovidiu Sas wrote:
>> So what is the outcome of this discussion?
>> Are we going to port the 'register_timer_process' from kamailio into
>> the sip-router?
>> This is a blocker for porting certain modules from kamailio to sip-router.
>
> As far as I can tell, the timer process in kamailio serves the same
> purpose as the slow timer process in ser, I would thus recommend to
> convert everything that uses register_timer_process in kamailio to use
> the slow timer process in ser.
>
> Of course I haven't investigated all the code in k. in detail, but it
> seems to me that the two mechanisms server the same purpose, given
> that k. doesn't have the slow timer process and we don't have separate
> timer processes in ser.
>
>  Jan.
>
>> On Fri, Mar 6, 2009 at 10:31 AM, Andrei Pelinescu-Onciul
>> <andrei at iptel.org> wrote:
>> > On Mar 06, 2009 at 14:53, Jan Janak <jan at iptel.org> wrote:
>> >> On 06-03 15:44, Daniel-Constantin Mierla wrote:
>> >> > Hello,
>> >> >
>> >> > On 03/06/2009 03:16 PM, Jan Janak wrote:
>> >> >> Hello,
>> >> >>
>> >> >> There are two functions in the implementation of timers in kamailio,
>> >> >> register_timer and register_timer_process. What is the different between those
>> >> >> two functions and which should be used when?
>> >> > the first one is to register a function to be executed by the main timer
>> >> > process. Second is to create a new time process dedicated to run a
>> >> > specific function.
>> >> >
>> >> >>  I noticed that, for example, the
>> >> >> htable module seems to be using them interchangeably, there is a modparam
>> >> >> which controls which function is gonna be used.
>> >> >>
>> >> >> Can we replace register_timer_process with register_timer function from the
>> >> >> sip-router core?
>> >> >>
>> >> > Doesn't ser support to create a new timer process? How is it in the
>> >> > timer module? Is the route executed by the main timer process?
>> >> >
>> >> > Idea behind dedicated timer process is to be able to execute timely
>> >> > operations there without affecting the main timer which deals with
>> >> > retransmissions, etc.
>> >>
>> >> I see, we have the concept of slow and fast timers, so in that case the stuff
>> >> that needs its own timer process should probably be executed from within the
>> >> slow timer handler.
>> >
>> > It depends, if it's very slow (e.g. can block for long periods of time
>> > in the timer handle), it will be better to run in its own process.
>> >
>> > After a quick look at what register_timer_process(f, p, i, f) does, it seems
>> > it's equivalent with:
>> >
>> > if (fork()==0) { sleep(interval); function(param); }
>> >
>> > (meaning one can have only 1 timer in one timer process, I haven't seen
>> > a way to register more)
>> >
>> > If you only need 1 timer in your extra timer process, this can be done
>> > in sr like above, but replacing fork() with fork_process(...).
>> > If you need several timers and you want to be able to register/delete
>> > them dynamically, you should use local_timer (local_timer is a
>> > generalized very efficient timer, designed to be run "by hand" in a
>> > single process).
>> >
>> > #include "local_timer.h"
>> >
>> > struct local_timer lt;
>> >
>> > if (fork_process(...,"my timer", ...)==0){
>> >    /* init */
>> >    init_local_timer(&lt, get_ticks_raw());
>> >    /* add timers */
>> >    local_timer_init(t1, handler1, param, 0);
>> >    local_timer_add(&lt, t1, S_TO_TICKS(10) /* 10 s*/, get_ticks_raw());
>> >    /* as many times as needed */
>> >    while(..){
>> >        /* do something, e.g. poll some fds, read or even sleep(..) */
>> >        /* periodically call local_timer_run  which checks if any timer
>> >           has expired and is so runs it */
>> >        local_timer_run(&lt, get_ticks_raw());
>> >        /* add more timers or delete some of them */
>> >        local_timer_del(&tl, t3);
>> >       ...
>> >    }
>> > }
>> >
>> >
>> > Andrei
>> >
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>> >
>