RE: Inspiron 6000 and CPU power saving

[Pallipadi, Venkatesh]

>-----Original Message-----
>From: linux-kernel-owner@xxxxxxxxxxxxxxx 
>[mailto:linux-kernel-owner@xxxxxxxxxxxxxxx] On Behalf Of 
>Michael (Micksa) Slade
>Sent: Sunday, October 15, 2006 7:18 PM
>To: linux-kernel@xxxxxxxxxxxxxxx
>Subject: Inspiron 6000 and CPU power saving
>
>I recently discovered that my Inspiron 6000 uses about 50% more power 
>idling in linux than in windows XP.  This means its battery life is 
>about 2/3 of what it could/should be.
>
>I guessed it might be the CPU, and did some tests.  The 
>results strongly 
>suggest as much.  These are the results I got for power consumption in 
>various situations.
>
>linux idle at 800MHz: 27W        
>linux idle at 1600MHz: 36W        
>linux raytracing at 800: 30W
>linux raytracing at 1600: 42W 
>
>windows idle (presumably 800MHz): 16W
>windows raytracing (presumably 1600MHz): 36W
>
>I've tried ubuntu dapper and ubuntu edgy, and RIP 10 (rescue disk) and 
>BBC 2.1 (rescue disk), and they all appear to have the same 
>issue.  The 
>machine's BIOS has no APM so I can't try it for comparison.
>
>I've tried noapic and "echo n > 
>/sys/module/processor/parameters/max_cstate", where n is 1 thru 4.  
>Neither appear to have any affect.
>
>I need help digging deeper.  I guess /proc/acpi/processor/CPU0/power 
>could give some insight but I'm not sure how to read the 
>numbers.  That 
>and "learn about ACPI" is all I can figure out so far.
>
>So where to from here?  I am prepared to spend a significant amount of 
>time researching and resolving the issue, so feel free to suggest 
>reading the ACPI spec or whatever if that's what it's going to take.
>
>Mick.
>

Output of 
#cat /proc/acpi/processor/CPU0/power/*
And
#cat /sys/devices/system/cpu/cpu0/cpufreq/*
Will be a good starting point.

Also, open a issue at bugme.osdl.org. It makes tracking the issues
easier that way.

Thanks,
Venki
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