[Opensim-dev] Proposal: Slowly making less of the Scene.Update() loop synchronous

[Melanie]

You need to carefully evaluate the issues this causes, specifically
the issue of something being started multiple times in parallel
because it's so slow.

Update()
{
	DoOneSlowThing();
	DoASlowSynchrnousThing();
}

converted to

Update())
{
	Util.FireAndForget(DoOneSlowThing, null);
	DoASlowSynchrnousThing();
}

may cause DoOneSlowThing to be run multiple times, concurrently. For
most Update() parts, that is ano-no.


Melanie


Justin Clark-Casey wrote:
> Whilst bug hunting today, I had reason to dive into the Scene.Update() loop.  This is called many times per second and 
> is in charge of updating the entire scene (moving avatars in response to client input, sending queued object updates to 
> the client stack, etc.).  The time taken by this loop increases as the number objects and avatars in the scene increase.
> 
> There's quite a lot of code hanging off this loop that looks like it could be carried out asynchronously instead.  This 
> particularly applies to some of the stuff being invoked via EventManager rather than called directly.
> 
> If the amount of synchronous code here could be reduced then this could improve scene performance and reduce instances 
> where delays in the called code temporarily freeze the update loop.  These problems can be very hard to track down.
> 
> Unless there are any countervailing technical arguments, I'd like to start slowly looking at this over the long term. 
> This might go so far as making some loop-triggered EventManager events asynchronous rather than synchronous.  I know 
> there is a fair amount of code that does depend on synchronous execution so any changes will be done slowly and carefully.
> 
> Regards,
>