cpu wierdo

can anyone explain this ?? dmesg shows only 5 cpus mpstat show 6

cpu 1 initialization complete - online
cpu 4 initialization complete - online
cpu 5 initialization complete - online
cpu 8 initialization complete - online
cpu 9 initialization complete - online
mgunix14 > mpstat
CPU minf mjf xcal intr ithr csw icsw migr smtx srw syscl usr sys wt idl
0 152 2 6232 112 100 270 11 20 24 0 2065 13 12 12 64
1 138 2 2482 203 191 376 19 25 56 0 1690 8 7 11 74
4 144 2 2234 195 185 371 18 25 56 0 1753 8 6 11 74
5 138 3 5640 413 203 259 12 21 23 0 1957 13 11 13 63
8 145 3 5440 200 190 253 11 20 24 0 1997 13 11 12 64
9 143 3 5943 296 285 230 12 20 42 0 2024 13 11 12 63

If no cpu's are running, what could print a message about the first one being initialized?

The messages that dmesg displays are from a buffer in the kernel. They get there by calling the kernel routine "printf". Your cpu 0 was the guy who wrote those messages. But first it had to locate the boot device, load the kernel into core and start it running.