[Olsr-users] [Olsr-dev] Broadcast Packets & Windows Routin

[Henning Rogge]

Am Samstag 23 Februar 2008 17:31:35 schrieb Hannes Gredler:
> actually we do ... b/c the timer buckets in the new timer code
> are not kept sorted ... so we really need to walk the timer slot
> every scheduling interval b/c we do not know what is in the slot
> and if a timer is about to fire.
Could this become a problem because the timers are not fired in order (later 
timers could be handled before earlier timers) ?

> i have made some experiments with sorted timer trees and given
> the frequent changes (read tc_edge updates) sorting timers did
> cost a lot of performance.
That would be bad, that's right.

> perhaps if we can invest some time in a rewrite that leads to lower
> consumption of timers (today we have roughly 2000 timers
> facing a network of 400 nodes), (and roughly 1200 are not really required
> :-/)
Sounds like a good idea.

> after that rewrite we might pick up the idea of keeping the timer list
> sorted and passing the timestamp of the first timer to select().
Maybe instead of a single timer tree we could keep a tree for each of your 
buckets (1 second interval). This way the number of timestamps to be sorted 
are lower than before.

> > 2.) olsrd can react to incoming network traffic at once, instead of
> > waiting for x milliseconds, this might be useful for plugins
>
> just for I/O purposes that makes a lot of sense to me now.
And maybe we prevent race conditions when some timers are fired in the wrong 
order... don't know if it's possible at the moment, but if we don't do so we 
have to document this behaviour somewhere...

Henning

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