[arch-general] powertop vs archlinux vs ubuntu

[Andrea Fagiani]

On 02/22/2010 04:53 AM, Brendan Long wrote:
> On 02/21/2010 04:55 PM, Xavier Chantry wrote:
>    
>> On Mon, Feb 22, 2010 at 12:42 AM, Stefano Z.<mie.iscrizioni at gmail.com>  wrote:
>>
>>      
>>> hi
>>>
>>> i've bought a new notebook (hp pavilion dm1-1150sl) and installed
>>> archlinux.
>>> i have see a strange thing with powertop, i'm running the vanilla arch kernel26,
>>> and i have see this behaviour:
>>> Cn                Avg residency       P-states (frequencies)
>>> C0 (cpu occupata)      (31,6%)
>>> C0                0,0ms ( 0,0%)
>>> C1 mwait          0,1ms ( 0,7%)
>>> C4 mwait          0,0ms (67,8%)
>>> Wakeups-from-idle per second : 31483,5  interval: 10,0s
>>> ---
>>> as you can see, i have a LOT of wakeups per seconds very low c1 states
>>> lot of c0 and c4 states,
>>> a wattmeter tell me that archlinux consume about 25/26watt
>>> Then i have boot a live ubuntu distro and see this:
>>> Cn                permanenza media    P-state (frequenze)
>>> C0 (cpu occupata)      ( 0,6%)
>>> polling           0,0 ms ( 0,0%)
>>> C1 mwait         26,7 ms (68,6%)
>>> C4 mwait          1,2 ms (30,8%)
>>> Wakeup-da-idle al secondo: 281,3        intervallo: 15,0s
>>> ---
>>> as you can see  the wakeups are a LOT lower than on arch and we have
>>> lot of c1 and c4 state,
>>> power consumption is about 20W, the same that i have with win7 (about 18/20w).
>>> For meaning about cX state see here:
>>> http://www.lesswatts.org/projects/powertop/powertop.php
>>>
>>> thanks!
>>>
>>>
>>>        
>> You didn't give enough information so we will need to check the basis :
>> - which cpufreq driver and governor are you using in both cases (check
>> cpufreq-info)
>> - what processes does powertop show as causes for wakeups ?
>> - what processes does top show in term of cpu usage ?
>>
>> Here is what I got in the last few minutes when i was writing this :
>> C4 mwait          3.4ms (92.5%)          800 Mhz    98.0%
>> Wakeups-from-idle per second : 279.4    interval: 10.0s
>>
>> I have a core 2 duo with acpi-cpufreq loaded and conservative governor.
>> $ grep cpufreq /etc/rc.conf
>> MODULES=(acpi-cpufreq)
>> DAEMONS=(syslog-ng net-profiles crond dbus hal alsa cpufreq storage-fixup)
>> $ grep governor /etc/conf.d/cpufreq
>> # valid governors:
>> governor="conservative"
>>
>>      
> They may just not have cpu-freq-utils installed maybe? I'm using
> laptop-mode-tools with compiz and GNOME running (but not doing anything)
> and it's saying 99.2% C4, 0.8% C0. This is with another Core2 and
> laptop-mode is set to use the powersave governor on battery (which is
> how I tested). When I plug it in, it jumps up to 25%, but I don't really
> care how active the processor is when it's on battery.
>
>    
Be sure to have cpu-freq-utils installed, as well as loading the right 
modules (acpi-cpufreq, cpufreq_ondemand, if you plan on using the same 
governor as ubuntu does), and add `cpufreq` to your DAEMONS array in 
rc.conf.
On my system, with laptop-mode-tools the powertop output is very similar 
to what Brendan said. Also, the 31k+ wakeups definitely mean there's 
some issue on your config.