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Adept II

About OGL Cayman support for DUAL DMA and dual setup/geometry engines!


I want to ask about OpenGL exposure of 6900 (cayman) features..

first it seems tessmark shows dual geometry/setup/tetesselator engine in cayman not working inogl.. how it will take to have an opengl supporting driver?

Also cayman has dual dma engine similar to nvidia fermi..

well nvidia has created a whitepaper showing how to exploit in opengl applications (named NVIDIA Quadro Dual Copy Engines) here:

seems you need two ogl contexts to exploit advantage of it via async buffer objects copies..

I question if right now using similar code will exploit cayman dual dma engines?

if not, will opengl driver take in near future? i.e. there are plans to expose it?

also a code sample showing how to exploit optimally once implemented would be good.. 



1 Reply

dual setup engine is automatically used. the tessmark numbers did not increase because of a separate issue: a corner case based on the specific tesselation shaders used in that demo, which should be fixed with the next catalyst.


the dual-dma engine is not enabled yet in opengl, but is planned. it should be quite automatic: upload will always use one dma, download will use the other. the only care is to avoid using blocking API (so ReadPixels should go to a PBO instead of to memory, and the app should check the status with a sync object)

Pierre B.