OpenCL or CUDA Which way to go?

Question

I'm investigating ways of using GPU in order to process streaming data. I had two choices but couldn't decide which way to go?

My criterias are as follows:

1. Ease of use (good API)
2. Community and Documentation
3. Performance
4. Future

I'll code in C and C++ under linux.

Answer 1

OpenCL

• interfaced from your production code
• portable between different graphics hardware
• limited operations but preprepared shortcuts

CUDA

• separate language (CUDA C)
• nVidia hardware only
• almost full control over the code (coding in a C-like language)
• lot of profiling and debugging tools

Bottom line -- OpenCL is portable, CUDA is nVidia only. However, being an independent language, CUDA is much more powerful and has a bunch of really good tools.

1. Ease of use -- OpenCL is easier to use out of the box, but once you setup the CUDA coding environment it's almost like coding in C.
2. Community and Documentation -- both have extensive documentation and examples, however I think CUDA has better.
3. Performance -- CUDA allows for greater control, hence can be better fine-tuned for higher performance.
4. Future -- hard to say really.

Answer 2

My personal experiences were:

1. API: OpenCL has slightly more complex api. However most time you will spent with writing kernel code, and here both are almost identical.

2. Community: CUDA has a much bigger community then OpenCL up til now, but this will probably about to even out.

3. Documentation: Both are very well documented.

4. Performance: We made the experience, that OpenCL drivers are not yet fully optimized.

5. Future: The future lies with OpenCL as it is an open standard, not restricted to a vendor or specific hardware!

This assessment is from 2010, so probably out-dated.

Answer 3

OpenCL all the way unless you have a specific reason to use CUDA. OpenCL runs well on multicores like Intel i7 in addition to running on GPUs. By using OpenCL you can run it on a much wider range of hardware from Droid cell phones to the IBM Power7 compute nodes of the world's largest supercomputer, Blue Waters, which is supposed to come online next year.