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 ---- [email protected] ---- http://xyzzyxyzzy.net/
RL: [email protected] - +41 44 724 8573 - http://www.zurich.ibm.com/~hud/
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