[Serdev] Re: was [Serusers] Timers

[Jiri Kuthan]

hi Richard,

thank you for your proposal. We already have some data structures
in mind for next revision of timers, which also addresses some other
timer-related issue. The thing is the time when we do that -- there
are quite many things we would love to do and variable timer in 
unfortunately not among those most highly prirotized.

-jiri

At 10:23 AM 5/25/2004, Richard wrote:
>Hi Jiri,
>
>More thoughts on the timer issue.
>
>The main issue to have multiple timer is the overhead
>to insert the element into the timer list. If only
>fixed timer is used, the event can be added at the end
>of the list and incur little cost. If we maintain a
>fixed timer list and use a flexible timeout value for
>an element, we can still add the element to the end of
>the list. When the element is called, the timeout
>value is reduced by fixed time amount and put back
>into the end of the list. The repeats until the
>timeout value becomes 0 or negative. Then the real
>processing is called.
>
>For example, the fixed timer is 20 second and the
>invite timeout for a call is 60 second. The
>t_on_failure is inserted to the timer list with a
>timeout value 60 seconds. First time it is called
>after 20 seconds, the timeout value becomes 40 seconds
>and the function is re-inserted back to the list. Then
>second time, it becomes 20 seconds. In the third time,
>it reduces to 0 and the callback function is finally
>executed.
>
>So the granularity of this is the fixed timer value,
>not the real timeout value specified. Most people
>would accept this. If someone wants really accurate
>value, they can use 10 seconds or even 5 seconds.
>
>Any comment?
>
>Thanks,
>Richard
>
>--- Jiri Kuthan <jiri at iptel.org> wrote:
>> There is only single-timer value in the current SER
>> code.
>> If all of your SER code uses stateful forwarding, it
>> will
>> use a single timer. Use two SERs, use stateful
>> forwarding
>> selectively, or wait till someone develops a
>> different
>> timer system.
>> 
>> -jiri
>
>
>
>        
>                
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--
Jiri Kuthan            http://iptel.org/~jiri/