[Opensim-dev] [Opensim-commits] r2413 - in trunk/OpenSim/Region: Application Environment Environment/Modules Environment/Scenes Examples/SimpleApp

[Dalien Talbot]

MW,

For the map, I think we need also to optimize the comms between the
simulator and grid server. We've done a bit of debugging with nebanon
(thanks neb! :), what happens is that the client fires off a *lot* of
MapBlockRequest packets.

Currently for every one of them we fire up an XMLHTTP request to the
grid. Needless to say that 15+ HTTP requests constitute a small-scale
DoS (especially since the UGA does not seem to be a super performant
http server) - this was causing HTTP timeout in some cases (hence
crash on the client - which i trapped now) - but at the moment
bringing up the map still causes a major hiccup both for UGA and for
the sim.

My thought is to time-throttle the requests - on the first
MapBlockRequest record the requested coordinates, and set up the timer
callback of, say, 3 seconds. every other MapBlockRequest that comes in
before the callback fires, does either of the two:
1) records the requested rectangle coords in the list (to be used
during http req)
2) updates the "requested rectangle" such that it is a rectangle
covering all the previous requests.

And resets the timer to 3 sec again.

Once the callback finally fires, the region collates all the data for
the request, and makes a *single* http request - either with the
"superset rectangle" (although i guess if the MapBlockRequests can
have disparate coordinates, this is potentially dangerous) - or -
ideally - with the list of rectangles (for which the current UGA might
need to be modded ?) Or, if we want to stay 100% backwards compatible,
just try to collate as much as we can (say, into up to 5x5 rect
requests), and the rest just shape not to fire too fast..

While this still does not solve the fundamental problem of scalability
of the UGA, this should make the things bit better.

I was planning to do that today hopefully, if Nebanon is available for
his kind help again :-)

/d


On Sun, Nov 18 2007 03:11:44 -0800,  <mw at opensimulator.org> wrote:
> Author: mw
> Date: 2007-11-18 03:11:44 -0800 (Sun, 18 Nov 2007)
> New Revision: 2413

> Attempt to get World Map working in Grid mode, will need to be using the grid asset server for it to work correctly and has only been quickly tested in a three region grid.