Warn if the user uses concurrent execution on a device which doesn't support it

src/drivers/cuda/driver_cuda.c

@@ -521,6 +521,9 @@ int _starpu_cuda_driver_init(struct _starpu_worker_set *worker_set)
 	init_context(worker_set, devid);
 #endif
 
+	if (worker_set->nworkers > 1 && props[devid].concurrentKernels == 0)
+		_STARPU_DISP("Warning: STARPU_NWORKER_PER_CUDA is %u, but the device does not support concurrent kernel execution!\n", worker_set->nworkers);
+
 	_starpu_cuda_limit_gpu_mem_if_needed(devid);
 	_starpu_memory_manager_set_global_memory_size(worker0->memory_node, _starpu_cuda_get_global_mem_size(devid));