[arch-general] powertop vs archlinux vs ubuntu

[Xavier Chantry]

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"