[Opensim-dev] some scalability tests...

[Impalah Shenzhou]

Just a stupid silly question: standalone or grid mode? If grid: where were
the ugaim servers? Same machine?

And a comment: 1024 regions? 8 hours for booting? Weird!


2010/1/22 Mic Bowman <cmickeyb at gmail.com>

> this is just fyi... and a very positive comment about how far opensim has
> come in recent months!
>
> as part of sizing the hw requirements for a mirror world project we're
> exploring... we wanted to do some scalability tests on the capacity of
> individual simulators in terms of the total number of regions. we wanted
> baseline numbers that focus on just the most simple region configuration: a
> completely empty region with default terrain. that is... this is JUST
> simulator overhead.
>
> all tests are done on one of our blades... dual proc, quad core with 16G
> ram running 64bit ubuntu. mono 2.6. and the tests are hosting 1024 regions
> in a 32x32 grid. the simulator configuration was our standard sciencesim
> config (XEngine, ODE, groups, wind, sun, etc).
>
> the first configuration ran all 1024 regions in *one* simulator. i honestly
> figured this would crash quickly. it didn't. we managed to get all 1024
> regions created and running well enough to walk around. it did take almost 8
> hours to start. the first couple regions were created in 1-2 seconds each.
> by the end, it was taking 4-5 minutes per region. clearly there is something
> quadratic in there (stop using linear lists, they are evil! :-). but it
> could have been the mono garbage collector. who knows... not sure its worth
> too much investigation because i can't imagine ever running a config like
> this for real. the simulator did crash when we opened the map in the viewer.
> the crash was caused because we ran out of sockets. while it was running,
> the simulator used just over 10G of ram and was running at about 700% CPU
> utilization (kind of scary to see load averages in the 900 range!).
>
> the second configuration ran 16 simulators each with 64 regions. startup
> took about 30 minutes (each of the 16 simulators avoided the quadratic
> "knee" we hit with the one big simulator). consumed about 11G of memory and
> was again consuming essentially all cycles on the machine (completely idle
> regions aren't very idle). all 16 simulators died just after startup with a
> "too many open files" error. not sure what caused it, but all of them died
> loading the same terrain dll as part of some wildcard function looking for
> dlls. that one is an interesting bug.
>
> the final configuration and the one we're shooting for in the short term
> runs 16 simulators, each with an 8x8 megaregion. again startup was around 40
> minutes. we might be able to cut that time down by starting all 16
> simulators simultaneously rather than 4 at a time. i really just wanted to
> make sure that some of the spikes we see in startup didn't cause failures
> (some race condition causes all threads to consume maximum processor cycles
> randomly on startup right now). and, well... it just worked. i figured the
> viewer would die horribly (it can't handle 250K "real" prims very well) but
> it survived just fine. turn off far clip with 8x8 megaregions providing
> neighbors and you are "capable" of contacting simulators in a 24x24 region
> range!. the view is pretty cool though it seems to not go beyond 12x12. :-)
> there are a bunch of problems (like you can't see the terrain in the region
> you're standing in)... but there are a LOT of little humps of terrain in
> view. oh... and it takes a lot of patience to get everything loaded.
>
> so... the conclusion... this opensim thing is pretty amazing! good work
> everyone.
>
> --mic
>
>
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