In the latest round of performance tests with OpenSim we invited our office as well as the contents of the OpenSim IRC channels to help do another performance test on OpenSim. At peak we managed to get 28 avatars into the sim and got a little bit more performance information about OpenSim and where our bottlenecks are, most notably discovering a few runaway memory problems when a ‘bad client’ connects.

I’ve attached at the bottom of this post, links to where you can get the profile dumps from this, if you are a programmer working on OpenSim you might be interested in taking a look at these. We use JetBrain’s dotTrace internally, so the files are formatted in dotTrace format  – there is two sets of tests, one labelled ‘pos*.dtc’ which indicates we were using the POS Physics Engine. The second set are called ‘ode*.dtc’ which utilize OpenDynamicsEngine. All of these tests are CPU tests, we dont have any memory profiles of the test, however memory usage on the server seemed quite acceptable.

Bullet points

• A client with high packetloss can cause the sim to create very large resend queues. One such client produced over 113MB of RAM used in resending packets. (Plus plenty of CPU time spent managing that large Queue.).
• There’s no indexers on EntityManager for child primitives, doing lookups on Child objects are very slow.
• POS Physics produces exponential load the more avatars moving around, ODE produces a linear load. POS consumes less however when agents < 10.
• ODE is notoriously unstable when being run under a profiler, crashing on average once every 3 minutes. POS remains stable, although produces nasty lag spikes.
• OpenSim is stable with 25 ordinary agents, however pcampbot (our stress tester) can very quickly disable a sim.

Dot Trace Files

Get them here: http://www.adamfrisby.com/Profiles/