a.stp

global count = 0
global bts
global target_pids

probe begin {
    warn("Start tracing")
}

probe process("/bin/sleep").begin {
    target_pids[pid()] = 1;
}

probe process("/bin/sleep").end {
    delete target_pids[pid()];
}

probe timer.profile {
    if (!target_pids[pid()])
        next;

    bt = sprint_ubacktrace()
    if (bt == "")
        next;
    bts[bt] <<< 1;
    if (++count >= 1000) {
        abort();
    }
}

probe timer.s(3) {
    abort()
}

probe end {
    n = 0
    foreach (bt in bts- limit 900) {
        n += strlen(bt)
    }
    println("n = ", n)
}