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Topic: CPU trouble (?)

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roberts

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Joined: Oct. 2003

Posted: Feb. 13 2007,15:46

Yes, indeed. Many laptops have power saving by reducing the cpu.

My thinkpad when running from battery defaults to half speed.
There is a BIOS setting to always use full speed.

Juanito

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Joined: Sep. 2005

Posted: Feb. 14 2007,03:47

I don't think this is anything to do with the Speedstep settings unless you have a way to permenently set them in BIOS - what I see with my machine is that it will always boot in the highest speedstep setting. Even if I set the CPU to the lowest setting, it will switch back to the highest setting on re-boot.

You can check the setting by:

cat /proc/acpi/processor/CPU0/performance

Under DSL my CPU is reported as 1.6GHz, 64MB cache but under DSL-N it is (correctly) reported as 1.6GHz, 2048MB cache - there does not seem to be a difference in performance though...

hs7sv

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Posts: 247
Joined: June 2005

Posted: Feb. 14 2007,07:13

My laptop is running at its slowest speed on DSL also. You can check the current MHz by:-

cat /proc/cpuinfo

My BIOS setting is to Dynamic. It works on openSUSE 10.2 but it doesn't work on DSL-3.2 and DSL-2.1b.

I'm searching for the way to set processor running at its fastest speed or adjusted dynamically.

--------------
"My advice is to just return hardware that does not work with a plain Linux kernel, right to the place where you bought it, and ask for your money back..."

Klaus Knopper

Juanito

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Posted: Feb. 14 2007,07:43

By highest, I meant highest power consumption (i.e. fastest speed). If you have a speedstep processor, you can change the power consumption/speed by:

echo x > /proc/acpi/processor/CPU0/performance

Where, on my machine, 1 >= x >= 7

It is possible to adjust the speedstep settings dynamically but this is much easier under Linux 2.6.x (DSL-N) than Linux 2.4.x (DSL), see:

DSL: http://damnsmalllinux.org/cgi-bin....t=14651

DSL-N: http://www.damnsmalllinux.org/dsl-n/f/viewtopic/403.html

lucky13

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Posts: 1478
Joined: Feb. 2007

Posted: Feb. 14 2007,16:25

Quote (hs7sv @ Feb. 14 2007,02:13)

My laptop is running at its slowest speed on DSL also....

Are you making apple-to-apple comparisons running the same applications under the same window manager, etc.? It figures your laptop would run a lot "slower" under DSL because DSL doesn't have the same overhead that a larger distro like SuSE has. That will account for a lot of difference. All it means is that you can run DSL longer per battery charge than SuSE or whatever else runs your CPU full steam.

I don't understand why some of you seem to consider it a "problem" that your CPU speed varies according to the demands placed on it by an operating system and the applications being run. I consider that a benefit regardless of what I'm running, especially if I need more than a couple hours between plugging it in.

--------------
"It felt kind of like having a pitbull terrier on my rear end."
-- meo (copyright(c)2008, all rights reserved)

12 replies since Feb. 06 2007,15:02

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