For interested monks, the original thread is 737662. It looks like you are being inconsistent in your definition of $processor. Your line $processor = `/aa/bin/get_bind_cpus.ksh` assigns a real value to $processor as does $processor = $1, whereas you attempt to read it as a reference in system("$os_command_table{$^O}{pbind} -b $$processor $$proc_id{$_} >/dev/null 2>&1"). I note that your subroutine get_cpu_used_by_other_proc actually returns \$processor, which is a pointer to the memory address, so if the final variable called is actually populated using this return value, your only inconsistency is $processor = `/aa/bin/get_bind_cpus.ksh`, which should be able to be fixed as per kyle's suggestion in 737880.