[Intel-gfx] CUDA port for intel graphics

[Gregory Diamos]

Hi,

My name is Gregory Diamos.  I am a PhD student at the Georgia Institute 
of Technology currently working on compiler backends for performing 
general purpose computation on GPU architectures.  My research group at 
Georgia Tech (CASL) group develops and maintains the Ocelot backend 
compiler for CUDA (http://code.google.com/p/gpuocelot/).  We are 
currently trying to perform architecture characterizations between 
different SIMD and multicore architectures and already have a detailed 
simulation and compilation infrastructure built around CUDA for NVIDIA 
GPUs, AMD GPUs, and Intel/AMD CPUs.  We are particularly interested in 
evaluating the Intel GPU architecture due to the tight integration 
between the CPU and GPU in GMA3150 and in the roadmaps for Sandybridge 
(http://en.wikipedia.org/wiki/Sandy_Bridge_%28microarchitecture%29).
After looking over the documentation in the programming guide, it seems 
like there is enough information of the ISA and buffer commands to do a 
backend for CUDA by generating an Intel binary for each CUDA program, 
and using buffer commands to setup memory, load the binary, and execute 
it.

I would appreciate it if people who have worked with the open source 
linux driver could provide the following information so that I can gauge 
the feasibility and level of effort of this project.

1. Is there an interface for writing directly to the GPU ring buffer 
that is exposed by the driver?  If not, would it be straightforward to 
add such an interface?

2. Are there any restrictions (security, DRM, etc) for loading/executing 
binaries on the media pipeline?

3. How modular is the driver?  Is there an interface for user-level 
applications to issue hardware commands in a way that is isolated and
time-shared with commands from the graphics driver?  If not, would it be 
straightforward to modify the driver to disable the graphics components 
of the driver and retain only an interface for passing commands to the 
device?

4. How is memory sharing between the CPU and GPU handled? Is it possible 
to map memory from the CPU's address space into the GPU's address space? 
  Sorry if this is already documented somewhere, I might have missed it.

I appreciate any help that you can offer.

Regards,

Gregory Diamos