CUDA multiple threads work with one pointer

Question

Well, for example I have some array Y and I want to increment Y[0] in multiple threads. If I only make Y[0]++ in __global__ function then Y[0] will be 1. So, how to resolve this?

Answer 1

Atomic operations are implementation dependent. If this compiles with no warnings, it is likely to work, but should be tested :-), or at least examine the assembler.

__global__ void mykernel(int *value){
    int my_old_val = atomicAdd(value, 1);
}

See the guide here