sycl with thread local storage

jimdempseyatthecove — Wed, 08 Oct 2025 15:21:20 GMT

I have an OpenMP program written without GPU offload.

I am in the process of adapting it to use GPU offload, should a GPU be present.

I would also adapt it to use a combination of concurrent OpenMP on CPU and GPU.

The original code used thread local storage:

#if defined(__linux) __thread int myCore = -1; // logical core (may be subset of physical cores and not necessarily core(0)) __thread int myHT = -1; // logical thread (may be subset of hw threads in core and not necessarily hwThread(0) in core) #else __declspec(thread) int myCore = -1; // logical core (may be subset of physical cores and not necessarily core(0)) __declspec(thread) int myHT = -1; // logical thread (may be subset of hw threads in core and not necessarily hwThread(0) in core) #endif

I now get an error:

1>C:\Diffusion\diffusion_tiled_HT1\HyperThreadPhalanx.h(83,19): : error : thread-local storage is not supported for the current target
1> 83 | extern __declspec(thread) int myCore;

While I can see that the CPU core and HT are meaningless within the GPU, they are significant within the CPU parallel regions.

Now I can circumvent the error by making an array for each variable and index it by the omp_get_thread_num(), but this isn't as efficient as using TLS.

Any comments on this would be welcomed.

Jim Dempsey

topic sycl with thread local storage in Intel® oneAPI DPC++/C++ Compiler

sycl with thread local storage