perf_output_copy
extern unsigned int perf_output_copy(struct perf_output_handle *handle,
#define perf_output_put(handle, x) perf_output_copy((handle), &(x), sizeof(x))
perf_output_copy(handle, &zero, pad);
perf_output_copy(handle, data->br_stack->entries, size);
perf_output_copy(handle, data->br_stack_cntr, size);
remainder = perf_output_copy(handle, addr, tocopy);