Re: 2.6.2: P4 ClockMod speed

From: Dominik Brodowski
Date: Mon Feb 16 2004 - 16:34:49 EST


Hi,

> I have a P4 2.4 running @ 3.12GHz.

So you overclock your CPU but then throttle it down... strange, but well...

> In 2.6.0, i could change it frequency
> via speedfreqd(8) up to its actual speed. Since 2.6.1, its max speed is
> locked on cpu *real* speed.

It's just a change of appearance -- the cpufreq driver uses the theoretical
speed of the CPU for its calculations; the actual CPU speed isn't
affected. You can verify this by looking at /proc/cpuinfo which still tells
3124.376 MHz.

By doing so it becomes easier to enter different frequencies e.g. into
/sys/devices/system/cpu/cpufreq/scaling_setspeed -- on my desktop, typing in
1200000 is easier than 12121224... [*]

Dominik

[*] The _actual_ CPU speed should be used on all cpufreq drivers where this
specific CPU frequency has implications to external components, e.g. LCD,
memory or pcmcia devices. Where only the _frequency ratio_ is of importance
[for loops_per_jiffy and friends] such "rounding" is acceptable, as long as
the ratio is constant.

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