thrust functor: “too many resources requested for launch”

问题

I'm trying to implement something like this in CUDA:

for each element

p = { p if p >= floor
      z if p < floor

Where floor and z are constants configured at the start of the test.

I have attempted to implement it like so, but I get the error "too many resources requested for launch"

A functor:

struct floor_functor : thrust::unary_function <float, float>
{
        const float floorLevel, floorVal;

        floor_functor(float _floorLevel, float _floorVal) : floorLevel(_floorLevel), floorVal(_floorVal){}

        __host__
        __device__
        float operator()(float& x) const
        {
            if (x >= floorLevel)
                return x;
            else
                return floorVal;
        }
};

Used by a transform:

thrust::transform(input->begin(), input->end(), output.begin(), floor_functor(floorLevel, floorVal));

If I remove one of the members of my functor, say floorVal, and use a functor with only one member variable, it works fine.

Does anyone know why this might be, and how I could fix it?

Additional info:

My array is 786432 elements long.

My GPU is a GeForce GTX590

I am building with the command:

`nvcc -c -g -arch sm_11 -Xcompiler -fPIC -Xcompiler -Wall -DTHRUST_DEBUG  -I <my_include_dir> -o <my_output> <my_source>`

My cuda version is 4.0:

$ nvcc --version
nvcc: NVIDIA (R) Cuda compiler driver
Copyright (c) 2005-2011 NVIDIA Corporation
Built on Thu_May_12_11:09:45_PDT_2011
Cuda compilation tools, release 4.0, V0.2.1221

And my maximum number of threads per block is 1024 (reported by deviceQuery):

Total amount of constant memory:               65536 bytes
  Total amount of shared memory per block:       49152 bytes
  Total number of registers available per block: 32768
  Warp size:                                     32
  Maximum number of threads per block:           1024
  Maximum sizes of each dimension of a block:    1024 x 1024 x 64
  Maximum sizes of each dimension of a grid:     65535 x 65535 x 65535

UPDATE::

I have stumbled upon a fix for my problem, but do not understand it. If I rename my functor from "floor_functor" to basically anything else, it works! I have no idea why this is the case, and would be interested to hear anyone's ideas about this.

回答1:

For an easier CUDA implementation, you could do this with ArrayFire in one line of code:

p(p < floor) = z;

Just declare your variables as af::array's.

Good luck!

Disclaimer: I work on all sorts of CUDA projects, including ArrayFire.

来源：https://stackoverflow.com/questions/10102417/thrust-functor-too-many-resources-requested-for-launch

标签

cuda

thrust