how to get max blocks in thrust in cuda 5.5

Question

The Thrust function below can get the maximum blocks of for a CUDA launch CUDA 5.0, which is used by Sparse Matrix Vector multiplication(SpMV) in CUSP, and it is a technique for setting up execution for persistent threads. The first line is the header file.

#include <thrust/detail/backend/cuda/arch.h>

thrust::detail::backend::cuda::arch::max_active_blocks(kernel<float,int,VECTORS_PER_BLOCK,TH    READS_PER_VECTOR>,THREADS_PER_BLOCK,(size_t)0)

But the function is not supported by CUDA 5.5. Was this technique not supported by CUDA 5.5, or should I use some other function instead?

Answer 1

There was never any supported way to perform this computation in any version of Thrust. Headers inside thrust/detail and identifiers inside a detail namespace are part of Thrust's implementation -- they are not public features. Using them will break your code.

That said, there's some standalone code implementing the occupancy calculator in this repository:

https://github.com/jaredhoberock/cuda_launch_config