userspace cpufreq governor not working as advertised

Hi,

I am using Suse Linux Enterprise Server 11.2, kernel version 3.0.13-0.27-default.
When I set the cpufreq governor to performance or userspace, the frequency of all the cores does not remain fixed and fluctuates very often. But, this should not be the case. The performance governor should always run the cores at the maximum frequency and userspace governor should run the cores at the user specified frequency.
I think there might be some temperature sensors which are causing the cpu frequency to fluctuate. I have the following modules of interest loaded

<lsmod output>
acpi_cpufreq 18803 0
processor 44407 1 acpi_cpufreq
thermal_sys 24622 1 processor
cpufreq_userspace 13162 2
cpufreq_powersave 12618 15
cpufreq_conservative 13863 0
mperf 12667 1 acpi_cpufreq

I think the thermal_sys module is causing the cpu frequency to fluctuate, so I want to unload it. To unload thermal_sys, I have to unload acpi_cpufreq. Once I unload acpi_cpufreq, all the interface to read cpu frequency are gone, so I cannot cross-check whether the cpu frequency fluctuates or not
Could you please help me in pointing out the issue

Regards
Rahul