[Opensim-dev] Performance optimization of complex ScienceSim regions

[James Stallings II]

wow indeed!

GO INTEL!!

On Mon, Aug 31, 2009 at 7:19 AM, Dr Scofield <DrScofield at xyzzyxyzzy.net>wrote:

>
> Lake, Dan wrote:
> > A few months back, we analyzed and proposed optimizations to scripting
> and timers on homogeneous regions which were dynamically created with up to
> 40,000 simple cubes and physics disabled. Considerable reductions in scene
> creation time and cpu utilization were achieved.
> >
> > The regions running on ScienceSim at this time have few scripts (less
> than 1% of objects), have large linked sets,  are loaded at startup from a
> database, and most have ODE physics enabled although very few objects are
> physical. This represents a completely different workload for OpenSim from
> our previous analysis. Some of these ScienceSim regions are extremely
> complex with between 60,000 and 140,000 prims. We have noticed that startup
> on these regions can take 45 minutes or more and consume 50% of a CPU once
> they reach a steady state with no users connected. We did not expect that
> high utilization since script counts were below 200 and no users were
> connected.
> >
> > We have identified 3 areas of optimization.
> >
> > 1. On startup, the region must be loaded from the database and all region
> modules must be started to prepare the region to run. On the largest
> ScienceSim regions, this step takes 20 minutes before the command prompt
> appears. We refer to this phase as the startup time.
> >
> > 2. The appearance of the OpenSim command prompt indicates that the
> Heartbeat thread has started up. Commands can be issued such as "create
> user" or "show stats", but the Heartbeat thread itself will remain in its
> first "beat" for up to 40 more minutes. During this time, users cannot
> connect and the stats are all listed as 0 and do not update. We refer to
> this phase as "first heartbeat time".
> >
> > 3. Once the region has completely started up, but before any users have
> connected, we notice that the CPU utilization seems unusually high for the
> amount of "action" in the scene. Less than 200 scripted or physical objects
> should not represent a high load, but the 140,000 static prims somehow
> consumed 50% of a CPU.
> >
> > Analysis
> >
> [lots of very good stuff]
>
> wow!
>
> --
> dr dirk husemann ---- virtual worlds research ---- ibm zurich research lab
> SL: dr scofield ---- drscofield at xyzzyxyzzy.net ---- http://xyzzyxyzzy.net/
> RL: hud at zurich.ibm.com - +41 44 724 8573 - http://www.zurich.ibm.com/~hud/<http://www.zurich.ibm.com/%7Ehud/>
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>



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