Agner wrote:
The GPU is still much faster than a CPU
with AVX2, so OpenCL will still be useful for some
purposes with massively parallel data.
I don't think that's generally true. A quad-core Haswell GT2 chip will have close to 500 GFLOPS on the CPU side, but only about 400 GFLOPS on the GPU side. Also, homogeneous computing is inherently more efficient due to requiring less data movement. And a GPU can easily stall due to a lack of out-of-order execution, insufficient parallelism, register space limits, and/or (shared) data bandwidth bottlenecks. The GTX 680 (3 TFLOPS) even fails to outperform an i7-3820 (230 GFLOPS): LuxMark OpenCL rendering!So the raw computing power is a bad indicator for effective performance. It will be much easier to achieve good performance out of AVX2. BTW. My
vector class library supports AVX2.
Yes, thanks for that, it should come in quite handy! |
New C++ vector class library new - Agner - 2012-05-30
New C++ vector class library new - Agner - 2012-06-05