__global__ void null(uint32_t *data);
__global__ void feedback(volatile void *bar, uint32_t *data);
__global__ void measure(int iter, volatile void *bar, uint64_t bus_addr, uint64_t *res, uint32_t *data);


__global__ void ipedma(volatile void *bar, uintptr_t bus_addr, volatile uint32_t *counter, volatile uint64_t *desc, uint32_t *data);