#!/usr/bin/perl
use strict;

my $ncpu    = shift or die "usage: $0 NUMCORES [--sleep]\n";
my $xarg    = shift;
my $afflist = "0-".($ncpu-1);

if($xarg eq '--child') {
    hog();
}
else {
    # parent process -> set affinity (inherited by all children)
    system("taskset -p -c $afflist $$");

    for(1..$ncpu) {
        # note: the exec() is important!
        # calling hog() directly would not trigger
        # the problem
        exec($0, -1, "--child") if fork() == 0;

        select(undef,undef,undef,0.01) if $xarg eq '--sleep';

    }
    for(;;) { sleep(10); }
}


# exec'd child: waste CPU
sub hog {
    for(;;) {}
}