On 8/20/06, Timothy Miller <[EMAIL PROTECTED]> wrote:
Here's an example: Many drawing engines have an "I am completely done" interrupt. DMA hardware and software use that to set up the transfer for the next block of commands. In the mean time, the GPU is IDLE. Just sitting there wasting time. What if we wanted an interrupt that said "I'm nearly done; go ahead and set me up for some more commands"? The only drawing engine I know of that does this is the one I designed for Tech Source. If you were to base your API around existing GPU designs, you would be forever unable to take advantage of this unusual feature, and you'd lose out on a potentially significant performance boost.
You need to look at the DirectX 10 specs. In DX10 there are multiple command queues. The GPU timeslices between them. If you load a shader program that is going to run in a loop for 10 minutes it will get time sliced with the other command queues. That allows the GUI to stay responsive while the shader program is running. DMA operations are just commands in the stream. Finishing a command queue doesn't generate an interrupt, if you want an interrupt put an interrupt command in the queue. DirectX 10 also implements virtual GPU memory so there is no issue with not having enough room for a command stream to fit into VRAM. There is only one address space so the page tables are not too complex. Don't build yesterday's hardware, graphic hardware is changing immensely with the increased use of the GPU. Non-GPU hardware is going to be embedded only in a couple of years. It is speculated that AMD bought ATI so that they could build a GPU that sits in an Opteron socket. Combining hypertransport and GPUs makes a lot of sense. I'm still not clear how scanout is going to work in that model. All of this is being driven by MS Vista. In a couple of years you won't be able to buy a computer without Vista capable hardware. -- Jon Smirl [EMAIL PROTECTED] _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
