static char data[4096] attribute((aligned(4096))) = {'a'};

void writer(int index) {
    std::string fname = "data" + std::to_string(index);
    int data_fd = ::open(fname.c_str(), O_RDWR | O_CREAT | O_APPEND, 0645);
    for (int32_t i = 0; i < 1000000; i++) {
        ::write(data_fd, data, 4096);
    }
    close(data_fd);
}

int main() {
    std::vectorstd::thread threads;
    for(int i = 0; i < 64; i++) {
        std::thread worker(writer, i);
        threads.push_back(std::move(worker));
    }
    for (int i = 0; i < 64; i++) {
        threads[i].join();
    }
    return 0;
}