Intel Clovertown vs. frequency scaling

[Andras.Horvath@cern.ch]

Hi,

I have a number of Clovertown (intel quadcore) machines and, even with
the latest 2.6.23, it seems to me that frequency scaling is not
supported (e.g. the /sys/devices/system/cpu/cpu0/cpufreq/* stuff does
not appear even though CONFIG_X86_SPEEDSTEP_CENTRINO is "y").

Is that as expected?

This is what the CPU (one core in one of the two sockets) looks like:

# head -24 /proc/cpuinfo 
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 15
model name      : Intel(R) Xeon(R) CPU           L5335  @ 2.00GHz
stepping        : 11
cpu MHz         : 1995.105
cache size      : 4096 KB
physical id     : 0
siblings        : 4
core id         : 0
cpu cores       : 4
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 10
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts pni monitor ds_cpl vmx tm2 ssse3 cx16 xtpr dca lahf_lm
bogomips        : 3994.09
clflush size    : 64


also:

# cat /proc/acpi/processor/CPU0/info 
processor id:            0
acpi id:                 0
bus mastering control:   no
power management:        yes
throttling control:      yes
limit interface:         yes

# cat /proc/acpi/processor/CPU0/power 
active state:            C2
max_cstate:              C8
bus master activity:     00000000
maximum allowed latency: 20000 usec
states:
    C1:                  type[C1] promotion[C2] demotion[--] latency[020] usage[00003940] duration[00000000000000000000]
   *C2:                  type[C2] promotion[--] demotion[C1] latency[040] usage[00013668] duration[00000000000359543325]


FWIW, I also have some other Core-based (Woodcrest, Intel L5160) systems
and cpufreq works fine there.

Any help or insight would be appreciated. 

(I'm experimenting with ways to lower the average power consumption of a
large number of servers, working my way through http://www.lesswatts.org
etc.  I'm willing to patch kernels, run tests, and I have proper power
meters to check the results.)

Andras