[Opensim-dev] 20,256 prim test

[Sean Dague]

First, nice work!  A few more comments spread throughout.

On Wed, Dec 12, 2007 at 09:52:01PM -0500, Teravus Ovares wrote:
> Greetings everyone
> 
> I was having fun tiling the ground and above with .25 meter cubes and ended
> up with this;
> http://opensimulator.org/images/d/d0/My20000Test_001.jpg
> 
> This test was conducted on a 100MB ethernet network.
> 
> The instance is running 3 regions, two with no prim in it.
> The sim is running ODE with a single agent.
> 
>  The client is running on a different machine then the sim.
> This was using the mySQL DB interface in Grid Mode
> 
> at 16,750 prim, the instance of OpenSim was using up 45% of a dual core 3Ghz
> processor(one core)
> at 20,256 prim, the instance of OpenSim was using up 22% of a dual core 3Ghz
> processor(both cores)
> In both cases the memory usage was around 145MB of RAM
> using 58 Threads
> 758 handles
> avg 1600 context switches
> 
> .NET Perf Info
> 11,750,740 = # Marshaling with unmanaged code(ODE)
> 2,839 = # GC handles
> 0.10 - 0.36  = % Time in GC
> 4,840 = Classes loaded
> 69 = Total Assemblies
> 
> .NET Locking and Threads
> 2 = locking contentions /sec
> 75,505+ and increasing = Queue Length peak
> 58 = Logical threads
> 4,294,967,033 = physical Threads
> 322 = current recognized threads
> 
> 
> A couple of notes.
> 
> It's really difficult to get to 20,000 prim.    The reason is DataStore
> Database backup takes an hour (based on prim duplications).
> At least with mySQL, this can be done asynchronously, I suggest we do that,
> otherwise you can DOS a sim simply by copying prim.
> IMHO, this is the *WORST* performance bog that we've got.  Even worse then
> the packet object create and discard.

For anything that large, a real database is definitely a requirement.
There are some changes that can be made to the way sqlite is used to
make it opperate a lot better at lower levels, but it was never intended
for anything on that scale.

> When logging into the sim, it takes about 3 minutes on a 100MB network to
> get all 20,256 prim at 600Kb/sec.  During that time, you can't really move
> because everything is being pushed through the Task throttle (this is by
> design).   Before this becomes general practice, we'll need to make sure we
> limit the amount of prim that go out at a time to a client.
> 
> One 3Ghz core could handle approx 18,000 prim before stalling in between
> frames.
> 
> Once again,
> Have a look at the picture.  It has the sim stats visible
> 
> Best Regards
> 
> Teravus Ousley

It would be really interesting to see how these changed with 2, 4, 8, 16
avatars.  I think we're seeing people pushing OpenSim on two different
vectors (lots of prims vs. lots of AVs) and there are very different
scaling issues on each of those vectors.

	-Sean

-- 
__________________________________________________________________

Sean Dague                                       Mid-Hudson Valley
sean at dague dot net                            Linux Users Group
http://dague.net                                 http://mhvlug.org

There is no silver bullet.  Plus, werewolves make better neighbors
than zombies, and they tend to keep the vampire population down.
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