#! stap -p4

# This exercises the perfom tapset.
# for this to work the following needs to be set up:
# 1) the processor on machine supported perfmon hardware
# 2) libpfm and libpfm-devel available on machine
# 3) systemtap translator built with "--enable-perfmon"

global h1, h2
global startt, starti

probe perfmon.counter("cycles") { h1=$counter; }
probe perfmon.counter("instructions") { h2=$counter; }

probe kernel.function("sys_read"){
    startt=read_counter(h1);
    starti=read_counter(h2);
}

probe kernel.function("sys_read").return {
    stopt=read_counter(h1);
    stopi=read_counter(h2);

    printf ("time = %d\n", stopt-startt);
    printf ("instructions = %d\n", stopi-starti);
}