... Just to learn how to generate a system call, I created a simple system call that basically sets and resets the value of a global parameter "PREFETCH". SYSTEM CALL code ********************************** int PREFETCH = 0; /* this is a global variable */ . ... To execute the sys_prefetch system call, I wrote a prefetch.c file with the following code. ************************code to call sys_prefetch***************** #include <linux/unistd.h> _syscall2 (int, prefetch, int, mode, int, nr_hints) . ...