Memory Allocation on GPU When to allocate memory on GPU and when to copy the data to & fro

Accelerated Computing CUDA CUDA Programming and Performance
1

Hi,

If the data is defined on the main(Host) program, is it required to copy the data from host to device? If its required to copy, then is memory allocation on GPU a must?

Example: I've an array with 10 (i.e. a[10]) elements initialized to 1,2,3 .. 10( a[0]..a[9]) on the host code.

The kernel call is:

addarr<<<N,1>>> (a);

As we are passing the base address of the array "a", is it still required to allocate memory on gpu and copy the contents?

Thanks in advance

2

Yes. See CUDA reference, please.

Regards,
MK

3

Zero-copy memory is also an (advanced) option for seldom-accessed data: Host memory accessible by device, allocated via cudaHostAlloc().