-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Mathias Fröhlich wrote: > Hi, > > On Thursday 24 May 2007, Tim Moore wrote: >> OSG reference counting doesn't need to be thread safe, even in the >> multi-threaded OSG modes, unless you're doing something very tricky. In >> any event, it shouldn't be turned on in the model reader initialization. > > Please don't! > It is there by intention. OK, but maybe this call shouldn't be buried in the initialization of the model loader. osgViewer::Viewer changes this mode for threading models that need it, and maybe your new viewer should do the same.
> I have a multithreaded viewer in the works and for that it is still useful to > have thread safe reference counting in place. > Also Having the database pager set up once we have the osgviewer code settled > we will do model loading in a thread that runs in parallel to the rest of the > application. And remember that we share some data across models. That model > cloning will need thread safe reference counting. > It does not cost much OTOH. Here's a somewhat unscientific test : src/Main/fgfs --fg-root=/home/moore/graphics/FlightGear/data/ - --aircraft=bo105 --disable-ai-models --geometry=1024x768 time of day: noon. Without thread safe reference counting (time in milliseconds): event 5.75 update 3.3 cull 1.75 draw 3.6 Total: 14.4 event 5.75 update 3.83 cull 1.83 draw 3.75 Total: 15.16 So, .76ms, or a 5% difference... I think this is fairly significant. The real cost will come when we start doing database paging: that's when a lot of Referenced objects will have their reference counts changed. In normal operation database paging doesn't need threadsafe reference counting. You have a good point about copying models. The thread safe mode can be set per Referenced object, which may be a better way of dealing with shared objects. Tim -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iD8DBQFGV/TDeDhWHdXrDRURAprLAJsHVi/Pb96Bx6vFfLzFNuUIkoiouwCgmqAr BEDvR4SEE4jEHdoIkZIrW0I= =0MLv -----END PGP SIGNATURE----- ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
