Re: is it really better speedstep-ich vs. p4-clockmod cpufreq driver?

[Riccardo Vestrini <riccardov@sssup.it>]

Jim Carter wrote:
> On Thu, 22 Jul 2004, Riccardo Vestrini wrote:
  >>it seems that speedstep-ich and acpi cpufreq driver have only two 
usable clock
>>frequencies, while p4-clockmod has eight
>>my cpu is: Intel Mobile Intel(R) Pentium(R) 4   CPU 3.06GHz stepping 09
> 
> 
> Definitely the voltage modulation is important to have.
you right, but I do not know if it is better to have a 0.3 GHz clock 
most of the time, or a 1.5 GHz with half voltage
> 
> Also as for strategies, if you have dynamic speed modulation, generally if
> the CPU is busy less than 73% of the time, then my machine should be run at
> the lowest speed, whereas if tasks are waiting to run then it should be put
> in the highest speed.  In a typical workload it's very rare for the needed
> throughput to be steadily between 73% and 100% so the intermediate speeds
> could be useful; this is true even if the available speed range is greater.  
> Actually, hardly anyone uses the full capacity of their CPU, and I don't
> even bother to run the dynamic modulation daemon, just leaving it at low
> speed all the time.  I switch manually if I have a big simulation to do.
> 
it is the same for me, cpu is almost always set to the lowest frequency, 
  but I often compile programs, so I need the full power

  I consider strange the fact that a more specific driver 
(speedstep-ich) is not able to put my laptop to half voltage + mininum 
clock (which is 0.3 GHz) while p4-clockmod is only able to adjust clock 
and not voltage;
probably these capabilities can be merged some way ...
I will try to write the authors

thank you

-- 

                                Riccardo Vestrini
                               <riccardov@sssup.it>

"Io ho una deformazione professionale, sono Ingegnere, e il problema in
quello che lei dice è l'essere umano, perché una macchina può sbagliare
ma l'essere umano ha sicuramente molti più difetti" --
sconosciuto ad un congresso, mentre un manager parlava di risorse umane

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