celeron *clutches at straws*

Hello all,

I am aware from searching google that cpufreq does not work on celerons. However at the same time I am just looking for clarification on something. here is my cpuinfo:

processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 2
model name : Mobile Intel(R) Celeron(R) CPU 2.00GHz
stepping : 7
cpu MHz : 1993.155
cache size : 256 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca
cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe cid
bogomips : 3932.16

Whereever I look on the internet a Family 15 Model 2 is reported as a Pentium 4!! I know that the chips are similar. So what is the truth? Is my chip cpufreq capable or not? If not, is there anything else I can do to save battery power?

Thanks a lot for your patience.

M

AFAIK no. Even though many parts of the CPU are similar so that they can be represented with the same CPUID, Celerons only do have one multiplier so SpeedStep is not supported on them.

You can use throttling (/proc/acpi/processor/./throttling or the cpufreq - p4-clockmod driver) to avoid the CPU heating so much the fan has to be enabled / has to turn at a higher speed which causes an increase in energy consumption. It doesn't save any real CPU power, though, as the CPU most likely is put into a good idle power state already (check for C2 or higher in /proc/acpo/processor/./power )

Dominik

Hi Dominik,

That is seriously useful thanks very much. I haven't looked in /proc/acpi/processor before! I have found that the C2 state is supported.

mdke@kallisto mdke $ cat /proc/acpi/processor/CPU0/power

active state:            C2
default state:           C1
bus master activity:     00000000

states:
C1: promotion[C2] demotion[--] latency[000]
usage[07824590] *C2: promotion[--] demotion[C1]
latency[002] usage[134432919]
C3: <not supported>

mdke@kallisto mdke $ cat /proc/acpi/processor/CPU0/info

processor id:            0
acpi id:                 0
bus mastering control:   yes
power management:        yes
throttling control:      yes
limit interface:         yes

Most useful of all will be your information on throttling, which i will experiment with. The last time I tried using throttling (through some kde gui on a mandrake live disk), it made some strange whining noises ;) Is it wholly safe? Noises make me uneasy... but of course cooling down the processor would be nice as my fan is on far too much! I'd like a bit of reassurance before I start though, so I'll post this reply back to the list. Any help is appreciated very much!

Thanks again,

Matt

Excellent. C3 would have been still better, though...

Search for singing or bad capacitors, throttling, and/or high-pitched noise on the acpi and lkml lists, then you'll read many good posts on this :-)

Dominik