Hi all, has any body used eclipse with osg. I tried using cmake but eclipse being an IDE and not a compiler, I failed to get a breakthrough. I will be very grateful to get guidance on this.
Thanx, Felix On 8/23/07, Robert Osfield <[EMAIL PROTECTED]> wrote: > > Hi All, > > Yesterday I did testing on my new Intel quad core + dual 7800GT system > and found performance in single threaded sometimes exceeded the > multi-threaded models, which is seriously screwy. So I investigated. > > Looking at the draw stats it was clear that the draw dispatch by two > threads/cores to two graphics context wasn't scaling well at all, with > the single threaded draw dispatch total time being lower than a > single draw dispatch when run multi-threaded. The per draw dispatch > stats for each camera should that running multi-threaded was more than > twice as slow. Clearly something in system between the CPU cores and > the GPU is scaling very very poorly. Is it CPU front side bus? Is it > the OpenGL driver not properly managing multiple graphics contexts? > Is the chipset not properly disapatching data in parallel to two > cards? I don't know the answer. > > As a test this morning I stuck a static Mutex into the > osgViewer::Renderer's draw dispatch code to prevent the draw dispatch > for the cameras from running in parallel - the cull can still run in > parallel, but not the draw dispatch. The result was startling - a > overall performance (i.e. fps) boost of 50-77% on the test models I've > thrown at it. The CullThreadPerCameraDrawThreadPerContext benefiting > the most. This also allows the multi-threaded models to out perform > single threaded as one would expect. > > I haven't tried out these changes on my Athlon dual core system, but > can't do this right away as I've taken the Gfx cards out of it for > this system, but perhaps others can do similar tests. My expectation > that different systems will exhibit different performance > characteristics when running multi-threaded - a well balanced system > should work best without serialization of the draw dispatch, but how > many of our modern systems are well balanced?? > > I have checked in my changes to osgViewer::Renderer and > osg::DisplaySettings to support the new serializer, so a svn update > will get these. Since the performance difference is so colossal on my > system and I expect that my system is closer to common set up of > modern multi GPU systems I've made the default to use the serialize to > true. > > To toggle the serializer: > > osgviewer mymodel.ive --serialize-draw ON > osgviewer mymodel.ive --serialize-draw OFF > > Or > > export OSG_SERIALIZE_DRAW_DISPATCH=ON > export OSG_SERIALIZE_DRAW_DISPATCH=OFF > osgviewer cow.osg > > Replace export for setenv or set according to what your native platform > is. > > It would be interesting to here from others with multi-CPU, multi-GPU > systems to see how they fair. > > I am also curious about systems like AMD's 4x4 system, where they have > two CPU sockets with a chipset connecting to the Gfx slots each. Does > any one have one? It could be that this system scales better than my > Intel quad core system. On this system I do actually have two > chipsets too - they provide 2 x 16x PCIExpress + 1x8x PCIExpress > bandwidth to the three Gfx slots, but it kinda looks like this isn't > working properly, or perhaps its the OpenGL driver that sucks at > multi-thread, multi-GPU... > > Robert. > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >
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