Are you using one of the AMD dual core machines?  That processor has the bad
design flaw that the TSC counter is not synced between core's so the kernel can't
use it. You might even be better off running a non SMP kernel on that box.

My machine has two dual cores AMD Opteron processor 280. Do I have
that TSC problem.


# dmesg | grep AMD
OEM ID: AMD      Product ID: HAMMER       APIC at: 0xFEE00000
CPU0: AMD Dual Core AMD Opteron(tm) Processor 280 stepping 02
CPU1: AMD Dual Core AMD Opteron(tm) Processor 280 stepping 02
CPU2: AMD Dual Core AMD Opteron(tm) Processor 280 stepping 02
CPU3: AMD Dual Core AMD Opteron(tm) Processor 280 stepping 02


processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 15
model           : 33
model name      : Dual Core AMD Opteron(tm) Processor 280
stepping        : 2
cpu MHz         : 2394.039
cache size      : 1024 KB
physical id     : 0
siblings        : 2
core id         : 0
cpu cores       : 2
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext
fxsr_opt lm 3dnowext 3dnow pni lahf_lm cmp_legacy ts fid vid ttp
bogomips        : 4790.36
clflush size    : 64


  Antonio Almeida