a question about the numa information on my machine

Hi,

   I don't know if this post is appropriately for this board. (If not,
which forum should I post to?)

   I am wondering if my machine is configured right.
   My machine equipped with two Intel Xeon  E5640 CPUs (each has 4 cores).
   The red hat version is Red Hat Enterprise 5.5 and linux kernel is
2.6.18-194.el5
   My question is when I check /sys/devices/system/node, there is only
one node0 directory.
   The information displayed by "numactl --show" is
policy: default
preferred node: current
physcpubind: 0 1 2 3 4 5 6 7
cpubind: 0
nodebind: 0
membind: 0

   Why there is only one node instead of two? Is there any thing wrong
with my machine?
   Also, I found a message in dmesg :
No NUMA configuration found
Faking a node at 0000000000000000-0000000318000000

   What should be a NUMA configuration look like?
   Another thing I think strange is the BIOS setting. Its default is SMP.
   When I try to change it to NUMA, I can only see one CPU after re-booting.
   Is it normal? (the machine model is Dell T5500)
   It will be very helpful if you can give me some direction.

   Thanks a lot.

David Lin