Problem with SMP 2.4.21 on Compaq Prolian 1600

["David Busby" <busby@pnts.com>]

Linux SMP,
    I've got a Compaq Proliant 1600-2xP3/500 machine that I cannot get SMP
to work correctly on.  At one point I had Win2K Server on there, and that
could see both processors.  (We're migrating to Linux).  So I installed
Slackware 9.0 (my personal favourite distro), then did some updates.  The
2.4.21 kernel was released (thank you) and I went to install.  The current
kernel 2.4.20 didn't have SMP enabled on that machine but I thought I'd try
2.4.21 with SMP.  So I did, using menuconfig I enabled SMP (only one option
right?) and then compiled the beast, config lilo and then thought I was good
to go.  Reboot was fine (after I remembered to include the PCI stuff that I
forgot the first compile) but cannot see the 2nd processor.  `cat
/proc/cpuinfo` (below) only shows one CPU in the machine :[.  Did I miss
something in the menuconfig?  I don't know where to even start
troubleshooting this.  I suppose I should also mention that I'm using the
software raid1 and 5 and booting from the raid1 device (/dev/md0).  Please
advise.

root@mimir:~# cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 7
model name      : Pentium III (Katmai)
stepping        : 2
cpu MHz         : 498.696
cache size      : 512 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 2
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca cmov
pat pse36 mmx fxsr sse
bogomips        : 996.14

root@mimir:~# cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid5]
read_ahead 1024 sectors
md0 : active raid1 sdb2[1] sda2[0]
      8360896 blocks [2/2] [UU]

md1 : active raid5 sde1[2] sdd1[1] sdc1[0]
      17772288 blocks level 5, 16k chunk, algorithm 0 [3/3] [UUU]

unused devices: <none>
root@mimir:~# cat /etc/lilo.conf
boot = /dev/md0
raid-extra-boot = "/dev/sda,/dev/sdb"
prompt
# Update this when you get this kernel working
# default = Linux_2.4.21
default = Linux_2.4.20
timeout = 60
change-rules
  reset
vga = normal
# 2.4.20
image = /boot/vmlinuz
  root = /dev/md0
  label = Linux_2.4.20
  read-only
# SMP 2.4.21
image = /boot/bzImage.2.4.21
  root = /dev/md0
  label = Linux_2.4.21
  read-only

David Busby
Systems Engineer
busby@pnts.com