SYCL problem with device pointer

SYCL development
8

Hi,

My previous suggestion introduced something like a control buffer (device buffer).
SYCL has facilities to actually do explicit copy within the command group. The copy function you can find in the SYCL under the SYCL functions for explicit memory operations section.

However, if you are running your parallel_for right after you copied onto device, you wouldn’t gain much from using this. I would suggest to try both ways : control (device) buffer as in my example or using sycl::handler::copy.

Here is a copy example I took directly from the SYCL specification for your convenience when browsing this forum topic.

const size_t nElems = 10u;

// Create a vector and fill it with values 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
std::vector<int> v(nElems);
std::iota(std::begin(v), std::end(v), 0);

// Create a buffer with no associated user storage
buffer<int, 1> b{range<1>(nElems)};

// Create a queue
queue myQueue;

myQueue.submit([&](handler &cgh) {
  // Retrieve a ranged write accessor to a global buffer with access to the first half of the buffer
  accessor<int, 1, access::mode::write, access::target::global_buffer> acc(b, 
          range<1>(nElems / 2), id<1>(0));

  // Copy the first five elements of the vector into the buffer associated with the accessor
  cgh.copy(v.data(), acc);
});

Hope this helps! :slight_smile:

-Georgi