Re: [PATCHSET] 0/3 Dynamic cpufreq governor and updates to ACPI P-state driver

[mru@kth.se (Måns Rullgård)]

mru@kth.se (Måns Rullgård) writes:

>> Most of the latest CPUs (laptop CPUs in particular) have feature 
>> which enable very low latency P-state transitions 
>> (like Enhanced Speedstep Technology-EST). Using this feature, 
>> we can have a lightweight in kernel cpufreq governor, 
>> to vary CPU frequency depending on the CPU usage. The 
>> advantage being low power consumption and also cooler laptops.
>
> So, I took this thing for a spin, but it didn't work at all.  I loaded
> the module, and did "echo demandbased > /sys/.../scaling_governor".
> This echo never returned, and the keyboard locked up.  After a little
> while, the fan started running at full speed.  I managed to cut and
> paste into an xterm and start top, which showed nothing unusual.  I
> could shut down and reboot normally.

I might add that this was on an Asus M2400E laptop.

/proc/cpuinfo:
processor	: 0
vendor_id	: GenuineIntel
cpu family	: 15
model		: 2
model name	: Mobile Intel(R) Pentium(R) 4 - M CPU 1.80GHz
stepping	: 7
cpu MHz		: 2070.179
cache size	: 512 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	: 4087.80

-- 
Måns Rullgård
mru@kth.se