[Opensim-dev] Phantom prims and memory usage?

[John Hopkin]

John Sheridan wrote:

>Ok, I'm trying a little bit of an experiment here and I'm wondering if 
>anyone else has tried this and had similar results?  We're running ODE 
>on Linux Ubuntu using a vps setup hosted on quad core Xeons.
>
>I'm going on the concept that if an object does not need any sort of 
>physical interaction that if its made phantom the server will in effect 
>use less resources.  In this case I have one server thats running six 
>sims with around 30,000 prims spread between them all.  After going 
>around and setting as many objects as possible to phantom (telephone 
>poles, windows, tables, chairs, misc props and anything thats not needed 
>to keep the avatar from falling out of the buildings) it appears as 
>though that server's memory usage has gone down from about 70% (740 
>megs) down to 45% (520 megs).  I would estimate that in total 
>approximately 15,000 to 20,000 prims were set to phantom.

Very interesting - thanks for looking into this.

It seems that in actual builds, those we see in use in SL, for
example, most prims don't need to be non-phantom but are, and it's not
surprising to find that your exercise reduces the cost.   I've
sometimes wondered if there's a case for saying that new prims should
be phantom by default, though I'm not necessarily suggesting that as a
course of action for OpenSim.  It certainly helps avatar movement when
a cleanup like you describe is done, especially with furniture,
poseballs etc, and it's well worth the time doing that even if only
for the sake of smooth operation.

Is there any indication of a corresponding drop in CPU usage,
especially when avatars are moving around in there?
-- 
John Hopkin