Power consumption HZ250 vs. HZ1000

From: Marc Ballarin
Date: Mon Jul 25 2005 - 09:15:33 EST

I did some measurements in order to compare power drain with HZ250 and
To measure the actual drain, I used the "smart" battery's internal measurement.
(Available with acpi-sbs in /proc/acpi/sbs/SBS0/SB0/state.)
No clue how accurate this is.

Here some battery details, in case someone knows:
charge reporting error: 25%
SB specification: v1.1 (with PEC)
manufacturer name: Panasonic
manufacture date: 2004-11-27
device name: 02ZL
device chemistry: Lion

Kernel: 2.6.13-rc3-mm1 + acpi-sbs

cpu family : 6
model : 13
model name : Intel(R) Pentium(R) M processor 1.60GHz
stepping : 6

The "ondemand" governor was running, using acpi_cpufreq. (Idle at 600MHz).

Systems was running X11/KDE to get a more or less realistic scenario. No
cron jobs, network traffic or additional applications. WLAN and built-in
display were disabled completely, all fans and LEDs were off, internal hard
disc was running. Additional peripherals: external keyboard, mouse, display
and externally-powered hard disk (USB).

The results are quite simple:
In both configurations the current settles between 727-729 mA
(Voltage ~16.5 V).

Some issues:

- C-states look strange:
active state: C2
max_cstate: C8
bus master activity: 00887fff
C1: type[C1] promotion[C2] demotion[--] latency[000] usage[00000010]
*C2: type[C2] promotion[C3] demotion[C1] latency[001] usage[01367471]
C3: type[C3] promotion[--] demotion[C2] latency[085] usage[00000000]

- I don't know, how much polling of the battery affects results. Reads always
block for ~10 seconds, and I used this behaviour for rate-limiting.

- Is this approach valid at all?

- I could repeat the test in single user mode with internal hard disc turned off.

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