atomic.hpp File Reference

#include "Kokkos_Core.hpp"

Go to the source code of this file.

Namespaces
namespace	Tests
namespace	Tests::Utils

Functions
template<typename T>
void	Tests::Utils::atomic_add (T *ptr, const T val)
	Atomically add val to *ptr using system scope and relaxed memory order.

Detailed Description

System-scope atomic operations

Kokkos uses desul for atomics and defaults to device scope on all backends. That is sufficient when only GPU threads (of the same device) share a memory location, but yields undefined behaviour when both CPU and GPU threads atomically access the same address (e.g. a Kokkos::View in Kokkos::SharedSpace).

This file provides a portable, system-scope atomic add with relaxed memory order.

For more information:

• https://nvidia.github.io/cccl/unstable/libcudacxx/extended_api/memory_model.html#atomicity
• https://nvidia.github.io/cccl/unstable/libcudacxx/extended_api/synchronization_primitives/atomic.html#concurrency-restrictions
• https://llvm.org/docs/AMDGPUUsage.html#memory-scopes
• https://rocm.docs.amd.com/projects/HIP/en/latest/how-to/hip_cpp_language_extensions.html#atomic-functions

Definition in file atomic.hpp.