kernel 2.6.34.1 and atom

1.升级内核到2.6.34.1发现atom D510 cpu显示为2个cpu，发现超线程没有支持，不知到什么原因，在内核中对超线程的支持已经选择了，不知道具体出了什么差错，请高人指点。SMT (Hyperthreading) scheduler support已经选择

dmesg |grep cpu
x86 PAT enabled: cpu 0, old 0x7040600070406, new 0x7010600070106
setup_percpu: NR_CPUS:4 nr_cpumask_bits:4 nr_cpu_ids:2 nr_node_ids:8
PERCPU: Embedded 14 pages/cpu @c1200000 s36436 r0 d20908 u1048576
pcpu-alloc: s36436 r0 d20908 u1048576 alloc=1*2097152
pcpu-alloc: [0] 0 1
Mapping cpu 0 to node 0
Mapping cpu 1 to node 0
HPET: 3 timers in total, 0 timers will be used for per-cpu timer

CONFIG_HPET_TIMER=y
CONFIG_HPET_EMULATE_RTC=y
CONFIG_DMI=y
# CONFIG_IOMMU_HELPER is not set
# CONFIG_IOMMU_API is not set
CONFIG_NR_CPUS=4
CONFIG_SCHED_SMT=y
CONFIG_SCHED_MC=y
CONFIG_PREEMPT_NONE=y