/proc/cpuinfo will tell you how many processors are enabled, but I want to know the total. I can see them all enumerated in:

[root@node02 mjs]# ls /sys/devices/system/cpu/
cpu0 cpu1 cpu2 cpu3 cpu4 cpu5 cpu6 cpu7 sched_mc_power_savings

but not so in /proc/stat

[root@node02 mjs]# cat /proc/stat
cpu 65142 1364 44298 148671393 162022 9689 1899 0
cpu0 1133 43 853 18664269 2848 21 146 0
cpu1 671 14 422 18666930 2149 7 6 0
cpu2 7917 84 8898 18652007 1003 1 3 0
cpu3 22206 45 6253 18481313 149921 9465 815 0
cpu5 8796 995 9985 18649240 919 1 16 0
cpu6 1021 1 504 18665804 2613 2 10 0
cpu7 10847 17 11415 18645977 1528 2 7 0

or /proc/cpuinfo

[root@node02 mjs]# grep process /proc/cpuinfo
processor : 0
processor : 1
processor : 2
processor : 3
processor : 5
processor : 6
processor : 7

so the question then becomes if I disable a cpu at boot, what then? Will it still show up in /sys later? If not, I suppose I can't put it back online later, can I.

-mark

To answer the original question:
How do you do that?

Try it?